CBSE Class 12

NCERT Solutions for Class 12 Physics Chapter 4 Moving Charges and Magnetism

NCERT Solutions for Class 12 Physics Chapter 4 Moving Charges and Magnetism part of NCERT Solutions for Class 12 Physics. Here we have given. NCERT Solutions for Class 12 Physics Chapter 4 Moving Charges and Magnetism

Question 1.
A circular coil of wire consisting of 100 turns, each of radius 8.0 cm carries a current of 0.40 A. What is the magnitude of the magnetic field B at the center of the coil?
Answer:

Question 2.
A long straight wire carries a current of 35 A. What is the magnitude of the Held B at a point 20 cm from the wire ?
Answer:

Question 3.
A long straight wire in the horizontal plane carries a current of 50 A in the north to south direction. Give the magnitude and direction of R at a point 2.5 m east at the wire.
Answer:

Question 4.
A horizontal overhead power line carries a current of 90A in the east to west direction. What is the magnitude and direction of the magnetic field due to the current 1.5 m below the line?
Answer:

Question 5.
What is the magnitude of magnetic force per unit length on a wire carrying a current of 8 A and making an angle of 30° with the direction of a uniform magnetic field of 0.15 T?
Answer:

Question 6.
A 3.0 cm wire carrying a current of 10A is placed inside a solenoid perpendicular to its axis. The magnetic field inside the solenoid is given to be 0.27 T. What is the magnetic force on the wire?
Answer:
I = 10 A, B = 0.27 T
1 = 3cm = 0.3m
and θ = 90°
F = BI 1 sin θ
=0.27×10 × 0.03 × sin90°
= 0.27×10 x 0.03 x 1
= 8.1 × 10^-2N.

Question 7.
Two long and parallel straight wires A and B carrying currents of 8*0 A and 5*0 A in the same direction are separated by a distance of 4-0 cm. Estimate the force on a 10 cm section of wire A.
Answer:

Question 8.
A closely wound solenoid 80 cm long has 5 layers of windings of 400 turns each. The diameter of the solenoid is 1.8 cm. If the current carried is 8.0 A, estimate the magnitude of B inside the solenoid near its center.
Answer:

Question 9.
A square coil of side 10 cm consists for 20 turns and carries a current of 12 A. The coil is suspended vertically and the normal to the plane of the coil makes an angle of 30° with the direction of a uniform horizontal magnetic field of magnitude 0.80 T. What is the magnitude of torque experienced by the coil?
Answer:
N = 20, A = 100 x 10^-4 m²
I = 12 A
B = 0.8 T
θ = 30°
Torque, τ = NI(\(\bar { A }\) x \(\bar { B }\))
= 20 x 12 x 100 x 10^-4 x 0.8 x sin 30°1
= 20 x 12 x 100 x 10^-4 x 0.8 x \(\frac { 1 }{ 2 }\)
= 0.96 Nm

Question 10.
Two moving .coil meters, M₁and M₂ has the following particulars:
R₁ = 10 Ω, N₁ = 30, A₁= 3.6 x 10^-3m², B₁= 0.25 T
R₂ = 14 Ω, N₂ = 42, A₂ = 1.8 x 10^-3 m², B₂ = 0.50 T (The spring constants are identical for the two meters). Determine the ratio of (a) current sensitivity and (b) voltage sensitivity of M₂ and M₁.
Answer:
Using Current sensitivity = NBA/k
For M₁ Current Sensitivity


Question 11.
In a chamber, a uniform magnetic field of 6.5G (1G = RHT) is maintained. An electron is shot into the field with a speed of 4.8 x 10⁶ ms^-1 normal to the field. Explain why the path of the electron is a circle. Determine the radius of the circular orbit,
(e =1.6 x 10^-19 C, m = 9.1 x 10^-31 kg).
Answer:

Question 12.
In Exercise 4.11 obtain the frequency of revolution of the electron in its circular orbit. Does the answer depend on the speed of the electron? Explain.
Answer:

Question 13.
(a) A circular coil of 30 turns and radius 8-0 cm carrying a current of 6-0 A is suspended vertically in a uniform horizontal magnetic field of magnitude 1.0 T. The field lines make an angle of 60° with the normal of the coil. Calculate the magnitude of the counter-torque that must be applied to prevent the coil from turning.
(b) Would your answer change, if the circular coil in (a) were replaced by a planar toil of some irregular shape that encloses the same area? (All other particulars are also unaltered)  (C.B.S.E. 1998 C )
Answer:
(a) Using τ = NBIA sin 9, we get
τ= 30 X 1 x 6 x n (8 X 10^-2)² sin 60
= 180 x it (8 x 10-²)² 0.866
= 3.13 N m
The magnitude of the counter-torque is 3 .13 N m
(b) Answer will not change because torque does not depend upon the shape of the coil provided it encloses the same area.

Question 14.
Two concentric circular coils X and Y of radii 16 cm and 10 cm, respectively, lie in the same vertical plane containing the north to south direction. Coil X has 20 turns and carries a current of 16 A: coil Y has 25 turns and carries a current of 18 A. The sense of the current in X is anticlockwise, and clockwise in Y, for an observer looking at the coils facing west. Give the magnitude and direction of the net magnetic field due to the coils at their center.
Answer:
For Coil X

Question 15.
A magnetic field of 100 G (1 G = 10^-4 T) is required which is uniform in a region of linear dimension about 10 cm and area of cross-section about 10^-3 m². The maximum current-carrying capacity of a given coil of wire is 15 A and the number of turns per unit length that can be wound round a core is at most 1000 turns m^-1. Suggest some appropriate design particulars of a solenoid for the required purpose. Assume the core is not ferromagnetic.
Answer:

We may take I = 10 A and n = 800. The given solenoid may have a length of 50 cm having 400 turns and area of cross-section = 5 x 10^-3m² (five times the given value.)

Question 16.
For a circular coil of radius R and N turns carrying current I, the magnitude of the magnetic field at a point on its axis at a distance x from its center is given by,

(a) Show that this reduces to the familiar result for field at the center of the coil.
(b) Consider two parallel co-axial circular coils of equal radius R, and number of turns N, carrying equal currents in the same direction, and separated by a distance R. Show that the field on the axis around the mid-point between the coils is uniform over a distance that is small as compared to R, and is given by,

(Such an arrangement to produce a nearly uniform magnetic field over a small region is known as Helmholtz coils.)
Answer:

(b) Let there be two coils as mentioned in the statement. The magnetic field in a small region of length 2d about the mid-point of the space between the two coils is given by,


Question 17.
A toroid has a core (non-ferromagnetic) of inner radius 25 cm and outer radius 26 cm, around which 3500 turns of a wire are wound. If the current in the wire is 11 A, what is the magnetic field
(i) outside the toroid
(ii) inside the core of the toroid, and
(iii) in the empty space surrounded by the toroid?
Answer:
(i) Zero

Question 18.
Answer the following questions:
(a) A magnetic field that varies in magnitude from point to point but has a constant direction (east to west) is set up in a chamber. A charged particle enters the chamber and travels undeflected along a straight path with constant speed. What can you say about the initial velocity of the particle?

(b) A charged particle enters an environment of a strong and non-uniform magnetic field varying from point to point both in magnitude and direction and comes out of it following a complicated trajectory. Would its final speed equal the initial speed if it suffered no collisions with the environment?

(c) An electron travelling west to east enters a chamber having a uniform electrostatic field in the north to south direction. Specify the direction in which a uniform magnetic field should be set up to prevent the electron from deflecting from its straight-line path.
Answer:
(a) The force on a charged particle moving inside the magnetic field is given by
\({ \vec { F } }_{ m }=q(\vec { v } \times \vec { B } )\)
The force on the charged particle coil bd zero (will remain undeflected), if v x B is zero. Therefore, either the initial velocity v is parallel or anti-parallel to the magnetic field B.

(b) The magnetic field exerts force on the charged particle, which is always perpendicular to its motion and hence does no work. Therefore, charged particle will have its final speed equal to its initial speed, provided it suffered no collision with the environment.

(c) Under the action of the electrostatic field, the electron will be deflected towards north (towards the positive plate). It will remain undeflected if the force due to the magnetic field is towards south. As the velocity: y of the electron is from west to east, the expression for the magnetic Lorentz force i.e. \({ \vec { F } }_{ m }=-e(\vec { v } \times \vec { B } )\) it tells that the magnetic field \(\vec { B } \) should be applied along the vertical and in downward direction. The direction of the magnetic field may be found by applying Fleming’s left-hand rule.

Question 19.
An electron emitted by a heated cathode and accelerated through a potential difference of 2.0 kV, enters a region with uniform magnetic field of 0.15 T. Determine the trajectory of the electron if the field (a) is transverse to its initial velocity, (b) makes an angle of 30° with the initial velocity.
Answer:
K.E, acquired by electron while passing through V

(b) When electron moves with velocity r making an angle of 30° with the direction of magnetic field, then r cos θ is


Question 20.
A magnetic field set up using Helmholtz coils (described in Exercise 4.16) is uniform in a small region and has a magnitude of 0.75 T. In the same region, a uniform electrostatic field is maintained in a direction normal to the common axis of the coils. A narrow beam of (single species) charged particles all accelerated through 15 kV enters this region in a direction perpendicular to both the axis of the coils and the electrostatic field. If the beam remains undeflected when the electrostatic field is 9.0 x 10⁵ V m^-1, make a simple guess as to what the beam contains. Why is the answer not unique.
Answer:

The given particle may be deutron.
The result is not unique because this e/m ratio can be true for He^{+ +} , Li ^{+ + +} etc.

Question 21.
A straight horizontal conducting rod of length 0.45 m and mass 60 g is suspended by two vertical wires at its ends. A current of 5.0 A is set up in the rod through the wires.”
(a) What magnetic field should be set up normally to the conductor in order that the tension in the wires is zero?
(b) What will be the total tension in the wires if the direction of current is reversed keeping the magnetic field the same as before? (Ignore the mass of the wires.) g = 9.8 ms^-2.
Answer:
(a) The tension in the wire is zero if the force on the current-carrying wire due to current is equal and opposite to the weight of the wire. This is, BIl= mg

(b) In case the current is reversed, the tension is equal to the force acting on the wire due to the magnetic field plus the weight of the wire. This is,
T = BlL + mg
= 0.26 x 5 x 0.45 + 60 x 10^-3 x 9.8
= 1.18 N.

Question 22.
The wires which connect the battery of an automobile to its starting motor carry a current of 300 A (for a short time). What is the force per unit length between the wires if they are 70 cm long and 1.5 cm apart? Is the force attractive or repulsive (H.S.E.B.2001)
Answer:

Since the currents in two wires are in opposite directions so the force is repulsive.

Question 23.
A uniform magnetic field of 1.5 T exists in a cylindrical region of a radius 10.0 cm, its direction parallel to the axis along east to west. A wire carrying a current of 7.0 A in the north to south direction passes through this region. What is the magnitude and direction of the force on the wire if,
(a) the wire intersects the axis,
(b) the wire is turned from N-S to the northeast-northwest direction?
(c) the wire in the N-S direction is lowered from the axis by a distance of 6.0 cm?
Answer:

Question 24.
A uniform magnetic field of 3000 G is established along the positive z-direction. A rectangular loop of sides 10 cm and 5 cm carries a current of 12 A. What is the torque on the loop in the different cases shown in Figure? What is the force on each case? Which case corresponds to stable equilibrium?

Answer:

Question 25.
A circular coil of 20 turns and a radius of 10 cm is placed in a uniform magnetic field of 0.10 T normal to the plane of the coil. If the current in the coil is 5.0 A, what is the
(a) total torque on the coil,
(b) the total force on the coil,
(c) average force on each electron in the coil due to the magnetic field?
(The coil is made of copper wire of cross-sectional area 10^-5 m², and the free electron density in copper is given to be about 10²⁹ m³)
Answer:

Question 26.
A solenoid 60 cm long and of radius 4.0 cm has 3 layers of windings of 300 turns each. A 2.0 cm long wire of mass 2.5 g lies inside the solenoid (near its center) normal to its axis; both the wire and the axis of the solenoid are in the horizontal plane. The wire is connected through two leads parallel to the axis of the solenoid to an external battery which supplies a current of 6.0 A in the wire. What value of current (with an appropriate sense of circulation) in the windings of the solenoid can support the weight of the wire? g = 9.8 ms^-2.
Answer:

Question 27.
A galvanometer coil has a resistance of 12 Q and the meter shows full-scale deflection for a current of 3 mA. How will you convert the meter into a voltmeter of range 0 to 18 V?
Answer:
Here 1=3 mA = 3 x 10^-3 A
Galvanometer resistance, G = 12 Ω The galvanometer can be converted into the voltmeter of range 0 to V (here V = 18 V) by connecting a high series resistance R given

Question 28.
A galvanometer coil has a resistance of 15Ω and the meter shows full-scale deflection for a current of 4 mA. How will you convert the meter into an ammeter of range 0 to 6?
Answer:

We hope the NCERT Solutions for Class 12 Physics Chapter 4 Moving Charges and Magnetism, help you. If you have any query regarding NCERT Solutions for Class 12 Physics Chapter 4 Moving Charges and Magnetism, drop a comment below and we will get back to you at the earliest.

NCERT Solutions for Class 12 History Chapter 5 Through the Eyes of Travelers Perceptions of Society are part of NCERT Solutions for Class 12 History. Here we have given NCERT Solutions for Class 12 History Chapter 5 Through the Eyes of Travellers Perceptions of Society.

NCERT Solutions for Class 12 History Chapter 5 Through the Eyes of Travellers Perceptions of Society

Question 1.
Write a note on the Kitab-ul-Hind.
Solution :

1. The Kitab-ul-Hind is written in Arabic and is simple and lucid.
2. It has 80 chapters on subjects such as religion, and philosophy, festivals, astronomy, alchemy, manners and customs, social life, weights and measures, iconography, laws and metrology.
3. Al-Biruni adopted a distinctive structure in each chapter, beginning with a question, following this up with a description based on Sanskritic traditions, and concluding with a comparison with other cultures. This almost geometric structure is remarkable for its precision and predictability.
4. He probably intended his work for peoples living along the frontiers of the subcontinent.

Question 2.
Compare and contrast the perspectives from which Ibn Battuta and Bernier wrote their accounts of their travels in India.
Solution :
Both have written them accounts in their different prospectives. While Ibn Battuta describe everything that impressed and excited him because of his novelty, Bernier had followed a different intellectual tradition. He wrote whatever he saw in India.
Bernier wanted to pin point the weakness of the Indian society and considered the Mughal India Inferior to European society. In his description Ibn Battuta recorded his observation about new culture, people, believes and values.

Question 3.
Discuss the picture of urban centres that emerges from Bernier’s account.
Solution :
During the seventeenth century, about 15 per cent of the population in India lived in cities. This was higher than the urban population in Western Europe in the same period. In spite of this Bernier described Mughal cities as “Camp towns”. These towns owed their existence, and depended for their survival on the imperial camp. He believed that these camp towns came into existence when the imperial court moved in and rapidly declined when it moved out. He stated that these “camp towns” did not have viable social and economic foundations. They were dependent on imperial patronage.

The above picture of urban centres that emerges from Bernier’s account does not seem to be correct because it is an oversimplified picture. There were all kinds of urban centres or towns i.e., manufacturing towns, trading towns, port towns, sacred centres and pilgrimage towns.

Question 4.
Analyse the evidence for slavery provided by Ibn Battuta.
Solution :
Travellers who left written accounts, sometimes took special inequalities for granted as a “natural” state of affairs. For example, is the evidence for slavery provided by Ibn Battuta that is as given below :

1. Slaves were openly sold in markets, like any other commodity and were regularly exchanged as gifts.
2. When Ibn Battuta reached Sind, he purchased “horses, camels and slaves” as gifts for Sultan Muhammad bin Tughlaq.
3. When he reached Multan, he presented the governor with, “a slave and horse together with raisins and almonds”.
4. Muhammad bin Tughlaq, informs Ibn Battuta, was so happy with the sermon of a preacher named Nasiruddin that he gave him “a hundred thousand tankas (coins) and two hundred slaves”.
5. According to Ibn Battuta’s accounts there were female slaves in the service of the Sultan. They were experts in music and dance. Female slaves were also employed by the Sultan to keep a watch on his nobles.
6. Slaves were generally used for domestic labour, particularly for carrying women and men on palanquins or dola.

Question 5.
What were the elements of the practice of sati that drew the attention of Bernier ?
Solution :
Bernier chose the practice of sati for detailed description. The elements of the practice of sati that drew the attention of Bernier were that while some women seemed to embrace death cheerfully, others were, forced to die. For example at Lahore, he saw a most beautiful young widow sacrificed. She was hardly twelve years of age and was forced by the Brahmanas and others towards the pyre and was burnt alive.

Question 6.
Discuss Al-Biruni’s understanding of the caste system.
Solution :
Al-Biruni’s description of the caste system in India was as given below :

1. He tried to explain the caste system by looking for parallels in other societies. For example, he noted that in Ancient Persia, there were four categories i.e., knights and princes; monks, fire-priests and lawyers; physicians, astronomers and other scientists; and finally, peasants and artisans. Thus, he stated that social divisions were not unique to India. He, however, pointed out that within Islam, Ml men were considered equal, differing only in their observance of piety.
2. He accepted the Brahmanical description of the caste system but disapproved of the notion of pollution. The conception of social pollution was, according to him, contrary to the laws of nature.

Thus, Al-Biruni’s understanding of the caste system was deeply influenced by his study of normative Sanskrit texts which laid down the rules governing the system from the point of view of the Brahmanas.

Question 7.
Do you think Ibn Battuta’s account is useful in arriving at an understanding of life in contemporary urban centres? Give reasons for your answer.
Solution :
Battuta’s observation about the cities of India.
(i)  According to him, Indian cities had many exciting opportunities and are useful for those who had the necessary drive, skill and resources.
(ii) The Indian cities were prosperous and densely populated.
(iii) These cities had colourful market trading in different kinds of goods.
(iv) Delhi was the largest city of India and had a lot of population. Daultabad was an another important city of India which challenged Delhi in size.
(v) The cities were not only the centre of economic transactions but also the centres of! social and cultural activities.
(vii) Most of the bazars in the cities had temple and mosques.
(viii) Cities also had fixed places for public performances by dancer, musicians and singer. He found that many towns derived their wealth and prosperity through the appropriation of surplus from villages.
(ix) Indian goods were in great demand in west Asia and South-east Asia. So the artisans and merchants earned huge profit.

Question 8.
Discuss the extent to which Bernier’s account enables historians to reconstruct contemporary rural society.
Solution :
Bernier’s account does not enable historians much to reconstruct contemporary rural society. His accounts contain discussions trying to place the history of the Mughals within some sort of a universal framework. He constantly compared Mughal India with contemporary Europe, generally emphasising the superiority of the latter.
His description of rural society was far from truth. For example, he thought that in the Mughal Empire, the Empire owned all the land and distributed it among his nobles. This had disastrous consequences for the economy and society. Owning to crown ownership of land, argued Bernier, landholders could not pass on their land to their children. So, they were averse to any long-term investment in the sustenance and expansion of production. This had resulted in uniform ruination of agriculture, excessive oppression of peasantry and a continuous decline in the living standards of all sections of society, except the ruling aristocracy. He also stated that there was no middle state in India.

The above description does not give us a true picture of rural society. None of the Mughal official document suggest that the state was the sole owner of land. Abul Fazl describes the land revenue as “remunerations of sovereignty”. In fact, during the sixteenth and seventeenth centimes, rural society was characterised by considerable social and economic differentiation. At one end were the big zamindars and on the other were the “untouchable” landless labourers. In between was the big peasant who used hired labour and engaged in commodity production, and the smaller peasant who could barely produce for his subsistence.

Question 9.
Read this excerpt from Bernier :
Numerous are the instances of handsome pieces of workmanship made by persons destitute of tools, and who can scarcely be said to have received instruction from a master. Sometimes they imitate so perfectly articles of European manufacture that the difference between the original and copy can hardly be discerned. Among other things, the Indians make excellent muskets, and fowling-pieces, and such beautiful gold ornaments that it may be doubted if the exquisite workmanship of those articles can be exceeded by any European goldsmith. I have often admired the beauty, softness, and delicacy of their paintings.

List the crafts mentioned in the passage. Compare these with the descriptions of artisanal activity in the chapter.
Solution :
(a) The following crafts have been mentioned in the passage :

• muskets;
• fowling-pieces;
• gold ornaments;
• paintings.

(b) There were imperial Karkhanas or workshops for the artisans where embroiderers, goldsmiths, painters, varnishers, joiners, turners, tailors and shoe-makers, manufacturer of silk, brocade and fine muslins were employed. They worked the whole day and in the evening they returned to their homes. The artisans were employed in manufacturing carpets, gold and silver cloths and various sorts of silk and cotton goods. Bernier also stated that the Indian artisans were expert in copying goods that it was difficult to differentiate between the original and the duplicate.

We hope the NCERT Solutions for Class 12 History Chapter 5 Through the Eyes of Travellers Perceptions of Society help you. If you have any query regarding NCERT Solutions for Class 12 History Chapter 5 Through the Eyes of Travellers Perceptions of Society, drop a comment below and we will get back to you at the earliest.

Here we are providing NCERT Solutions for Class 12 English Flamingo Poem 3 Keeping Quiet. Students can get Class 12 English Keeping Quiet NCERT Solutions, Questions and Answers designed by subject expert teachers.

Keeping Quiet NCERT Solutions for Class 12 English Flamingo Poem 3

Keeping Quiet NCERT Text Book Questions and Answers

Keeping Quiet Think it out 

Question 1.
What will counting up to twelve and keeping still help us achieve?
Answer:
The poet advises his readers to count up to twelve and keep still to achieve a sense of togetherness. The poet advises on introspection by taking a break from the mundane activities of life. He compares this with the earth that seems quiet and yet nurtures so much life on it.

Question 2.
Do you think the poet advocates total inactivity and death?
Answer:
No, the poet does not advocate total inactivity and death. He feels that peace and tranquillity should*not be confused with lethargy. He compares lethargy to death itself. He wants a perceptive silence in which people are not obsessed with apparent progress. The self- introspection might also lead to less violence and destruction.

Question 3.
What is the “sadness” that the poet refers to in the poem?
Answer:
The “sadness” that the poet talks about refers to the ceaseless activity that leaves little time for self-analysis and finally leads to doom. This mindless activity leads men to destruction. They kill whales and injure themselves by chemicals or fire. He also pleads with mankind to end environmental degradation. Such activities lead to a situation that is a mere illusion of victory, but in actuality, is fatal.

Question 4.
What symbol from nature does the poet invoke to say that there can be life under apparent stillness?
Answer:
The poet invokes a powerful symbol of the Earth to educate that there can be life under apparent stillness. He says that Earth is a great teacher. In its quietness, its strong message resounds. It seems silent and yet nurtures so much life on it. The poet wants to begin his mission of giving our lives a thought. He wants us to be productive in our silence.

Keeping Quiet Extra Questions and Answers

Keeping Quiet Short Answer Questions

Question 1.
How are the first two lines different from the last two lines of the poem?
Answer:
The first two lines appeal to the reader to count till twelve and keep silent. The speaker expresses his desire for silence and peace as an answer to end mindless activity. Whereas, in the last two lines, he wants the people to begin the exercise at their own level. He moves on to initiate this activity elsewhere.

Question 2.
What is the kind of a world that Neruda dreams of?
Answer:
Neruda dreams of a calm, quiet and a peaceful world where the hallmark would be togetherness. He dreams of a world which is free of destructive activity.

Question 3.
According to the poet, silence is profound. Justify.
Answer:
According to the poet, silence is the hope for a peaceful world. Silence is opposed to lethargy as it is the time for introspection. In the present world, the poet feels that people are obsessed with seeming progress that . leads to their destruction.

Question 4.
Earth is the best teacher. Why does the poet feel so?
Answer:
The poet feels that Earth is the best teacher because it is quiet and calm, yet nurtures so much life on it. He implies that such silence is productive as serenity and tranquillity leads to progress.

Keeping Quiet Value Based Question

Question 1.
The poem “Keeping Quiet” is based on the theme of universal peace and tranquillity. Justify.
Answer:
Neruda begins the poem by urging his readers to observe a moment of stillness and silence. He longs for a moment sans communication and activity where man is at complete peace with himself and his surroundings. _ This “exotic moment” would be a moment of universal peace. He feels, humans are preoccupied with their own progress which deprives them of the true pleasure of living. They merely exist and indulge in meaningless activities like that of the fishermen harming the whales. Man through his meaningless trysts endangers the environment and his own life.

The poet thus urges people to cleanse their souls, wear clean clothes and walk peacefully in universal brotherhood. The poet however, does not want the readers to confuse tranquillity with total inactivity, which meant sluggishness and death. He urges people to be unselfish and wants them to allow a moment of silence to interject their fast-moving, useless lives. He wants people to look upon Earth as a teacher, to fulfil a greater purpose in life.

Give examples from the poem of the following poetic devices.

Personification
“face of the earth”

Synecdoche
“not move our arms so much”

Hyperbole
“victory with no survivors”

Contrasting/antithetical imagery
“wars/ walk about with their brothers in shade”

NCERT Solutions for Class 12 Biology Chapter 5 Principles of Inheritance and Variation

These Solutions are part of NCERT Solutions for Class 12 Biology. Here we have given NCERT Solutions for Class 12 Biology Chapter 5 Principles of Inheritance and Variation

Question 1.
Mention the advantages of selecting pea plant for experiment by Mendel.
Solution:

1. The plant shows clear-cut contrasting characters.
2. Hybrids are perfectly fertile.
3. Genes for the seven contrasting characters are located on seven separate chromosomes.
4. Easy to cultivate.
5. The floral structure is suitable for artificial pollination.
6. Short growth period and life cycle.
7. Cross-pollination is easy if self-pollination is prevented.
8. Pure breeding varieties are available

Question 2.
Differentiate between the following:

1. Dominant and Recessive
2. Homozygous and Heterozygous
3. Monohybrid and Dihybrid

Solution:

1. Differences between dominant and recessive genes are as follows :
   
2. Differences between homozygous and heterozygous are as follows :
   
3. Differences between monohybrid and dihybrid cross are as follows :
   

Question 3.
A diploid organism is heterozygous for 4 loci, how many types of gametes can be produced?
Solution:
A diploid organism heterozygous for 4 loci will have the supported genetic constitution YyRr for two characters. The alleles Y-y and R-r will be present on different 4 loci. Each parent will produce four types of gametes – YR, Yr, yR, yr.

Question 4.
Explain the law of dominance using a monohybrid cross.
Solution:
The Law of dominance states that when a pair of alleles or allelomorphs are brought together in F₁ hybrid, then only one of them expresses itself, masking the expression of the other completely. Monohybrid cross was made to study the simultaneous inheritance of a single pair of Mendelian factors. The cross in which only alternate forms of a single character are taken into consideration is called a monohybrid cross. The trait which appeared in the F₁ generation was called dominant and the other which did not appear in the F₁ population was called recessive.

Thus, when a pair of alleles are brought together in an F₁ hybrid, then only one of them expresses itself masking the expression of the other completely. In the above example, in Tt – F₁ hybrid (tall) only ‘T’ expresses itself so dominant, and ‘t’ is masked so recessively. Thus, this’ proves and explains the law of dominance.

Question 5.
Define and design a test-cross.
Solution:
The crossing of F₁ individuals having dominant phenotype with its homozygous recessive parent is called test cross. The test cross is used to determine whether the individuals exhibiting dominant character are homozygous or heterozygous.
Example: When a tall plant (TT) is crossed with the dwarf plant (tt) in the F₁, generation only tall plant (Tt) appears which is then crossed with homozygous recessive (tt) in a test cross.

In the given test cross between tall heterozygous F₁ hybrid with dwarf homozygous recessive parent produces tall and dwarf progeny in equal proportion indicating that F : hybrids are heterozygous.

Question 6.
Using a Punnett square, work out the distribution of phenotypic features in the first filial generation after a cross between a homozygous female and a heterozygous male for a single locus.
Solution:
When a heterozygous male tall plant (Tt) is crossed with the homozygous dominant female tall plant (TT), we get two types of gametes in males: half with T and a half with t, and in females, we get only one type of gametes i.e., T.

From the Punnett square it is seen that all the progeny in the F generation are tall (Tt), 50% homozygous tall (TT), and 50% heterozygous tall (Tt).

Question 7.
When a cross is made between a tall plant with yellow seeds (TtYy) and a tall plant with the green seed (Ttyy), what proportions of phenotype in the offspring could be expected to be

1. tall and green
2. dwarf and green

Solution:

Phenotypes of the offsprings –
Tall Yellow : 3
Tall Green : 3
Dwarf Green: 1
Dwarf Yellow: 1
(a) Proportion of tall and green is 3/8.
(b) Proportion of dwarf and green is 1/8.

Question 8.
Two heterozygous parents are crossed. If the two loci are linked what would be the distribution of phenotypic features in F₁ generation for a dihybrid cross?
Solution:
Two heterozygous parents (i.e. GgLl and GgLl) are crossed and the two loci are linked then the cross will be

This means, if ‘G’ represent grey body (dorhinant), ‘g’ black body (recessive), ‘L’-long (dominant) and ‘I’-dwarf (recessive) then the distribution of phenotypic features in F1 generation will be 3 : 1 i.e. 3/4 will show the dominant feature, grey and long, either in homozygous (GGLL) or in heterozygous (GgLl) condition and 1/4 will show the recessive feature, black and dwarf (ggll).

Question 9.
Briefly mention the contribution of T.H. Morgan in genetics.
Solution:
TH Morgan is a Geneticist who got Nobel Prize.

• He found fruit fly (Drosophila Melanogaster) to be an experimental material as it was easy to rear and multiply.
• The established presence of genes over the chromosomes.
• Principle of linkage and crossing over.
• Discovered sex linkage and crossing over.
• He observed mutations.
• The developed technique of chromosome mapping,
• Wrote the book “The theory of Gene”.

Question 10.
What is pedigree analysis? Suggest how such an analysis, can be useful.
Solution:
A record of inheritance of certain genetic traits for two or more generations presented in the form of a diagram of family tree is called pedigree. Pedigree analysis is study of pedigree for the transmission of particular trait and finding the possibility of absence or presence of that trait in homozygous or heterozygous state in a particular individual. Pedigree analysis is useful for the following:

• It is useful for the genetic counsellors to advice intending couples about the possibility of having children with genetic defects like haemophilia, colour blindness, alkaptonuria, phenylketonuria, thalassemia, sickle cell anaemia (recessive traits), brachydactyly and syndactyly (dominant traits).
• Pedigree analysis indicates that Mendel’s principles are also applicable to human genetics with some modifications found out later like quantitative inheritance, sex linked characters and other linkages.
• It can indicate the origin of a trait in the ancestors, e.g., haemophilia appeared in Queen Victoria and spread in royal families of Europe through marriages.
• It helps to know the possibility of a recessive allele to create a disorder in the progeny like thalassemia, muscular dystrophy, haemophilia.
• It can indicate about the harm that a marriage between close relatives, may cause.
• It helps to identify whether a particular genetic disease is due to a recessive gene or a dominant gene.
• In certain cases it may help to identify the genotypes of offspring yet to be born.

Question 11.
How is sex determined in human beings?
Solution:
In humans, there are 23 pairs of chromosomes. 22 pairs of these chromosomes do not take part in sex determination called autosomes. The 23rd pair determines the sex of an individual called allosome or sex chromosome. If it is XX then female, if XY then male. The presence of Y¹ makes a person male. Human females produce only 1 type of gamete 22 + X. In males, it could be 22 + X or 22+ Y.

Question 12.
A child has blood group O. If the father has blood group A and mother blood group B, work out the genotypes of the parents and the possible genotypes of the other offsprings.
Solution:
If the father has blood group A i.e., I^AI^A (homozygous) and mother has blood group B i.e., I^BI^B (homozygous) then all the offsprings will have blood group AB (I^AI^B) and not blood group O.


Thus the genotypes of the parents of child with blood group O will be I^Ai and I^Bi There is the possibility of 3 other types of blood groups of offsprings besides O blood group offspring. They are I^Ai (blood group A). I^Bi (blood group B) and I^AI^B (blood group AB).

Question 13.
Explain the following terms with an example:

1. Codominance
2. Incomplete dominance

Solution:
Codominance (1 : 2 : 1) — It is the phenomenon of two alleles (different forms of a Mendelian factor present on the same gene locus on homologous chromosomes) lacking dominant- recessive relationship and are able to express themselves independently when present together.

Example – AB blood group: Alleles for blood group A(I^A) and blood group B(I^B) are codominant so that when they come together in an individual, they produce blood group AB. It is characterized by the presence of both antigen A (from I^A) and antigen B (from I^B) over the surface of erythrocytes.

Incomplete dominance (1 : 2 : 1) – It is the phenomenon where none of the two contrasting alleles being dominant so that expression in the hybrid is intermediate between the expressions of the two alleles in the homozygous state. F₂ phenotypic ratio is 1 : 2 : 1, similar to genotypic ratio. Example-In Mirabilis jalapa (Four o’clock) and Antirrhinum majus (Snapdragon or dog flower), there are two types of flower colour generation are of three types- red, pink and white flowered in the ratio of 1 : 2 : 1. The pink colour apparently appears either due to the mixing of red and white colours (incomplete dominance).

Question 14.
What is point mutation? Give one example.
Solution:
Point mutation is a gene mutation that arises due to a change in a single base pair of DNA.
Example: Sickle-cell anaemia.
Substitution of a single nitrogen base at the sixth codon of the β- globin chain of haemoglobin molecule causes the change in the shape of the R.B.C. from biconcave disc to the elongated shaped, structure which results in sickle cell anaemia.

Question 15.
Who had proposed the chromosomal theory of inheritance?
Solution:
Sutton and Boveri proposed the chromosomal theory of inheritance. The theory believes that chromosomes are vehicles of hereditary information that possess mendelian factors or genes and it is the chromosomes which segregate and assort independently during transmission from one generation to the next.

Question 16.
Mention any two autosomal genetic disorders with their symptoms
Solution:
Cystic fibrosis is an autosomal recessive disorder of infants, children, and young adults that is due to a recessive autosomal allele present on chromosome 7. It is common in Caucasian Northern Europeans and White North Americans. The disease gets its name from the fibrous cysts that appear in the pancreas. In 70% of cases, it is due to the deletion of three bases. It produces a defective glycoprotein. The defective glycoprotein causes the formation of thick mucus in the skin, lungs, pancreas, liver, and other secretory organs. Accumulation of thick mucus in the lungs results in obstruction of airways. Because of it, the disease was also called mucoviscoides, Mucus deposition in the pancreas blocks secretion of pancreatic juice. There is a maldigestion of food with high-fat content in the stool. The liver may undergo cirrhosis and there is impaired production of bile. Vasa deferentia of males undergo atrophy.

Huntington’s disease or Huntington’s chorea is a dominantly autosomal inherited disorder in which muscle and mental deterioration occur. There is gradual loss of motor control resulting in uncontrollable shaking and dance-like movements (chorea). The brain shrinks between 20-30% in size followed by slurring of speech, loss of memory, and hallucinations. Life expectancy averages 15 years from the onset of symptoms. This disorder does not occur till the age of 25 to 55. The defective gene is dominant autosomal, located on chromosome 4. This defective gene has 42 -100 repeats of CAG instead of 10-34 repeats in the normal gene. The frequency of this disorder is 1 in 10000 to 1 in 20000.

We hope the NCERT Solutions for Class 12 Biology Chapter 5 Principles of Inheritance and Variation help you. If you have any query regarding NCERT Solutions for Class 12 Biology Chapter 5 Principles of Inheritance and Variation, drop a comment below and we will get back to you at the earliest.

Here we are providing NCERT Solutions for Class 12 English Flamingo Poem 6 Aunt Jennifer’s Tigers. Students can get Class 12 English Aunt Jennifer’s Tigers NCERT Solutions, Questions and Answers designed by subject expert teachers.

Aunt Jennifer’s Tigers NCERT Solutions for Class 12 English Flamingo Poem 6

Aunt Jennifer’s Tigers NCERT Text Book Questions and Answers

Aunt Jennifer’s Tigers Think it out

Question 1.
How do “denizens” and “chivalric” add to our understanding of the tiger’s attitudes?
Answer:
Unlike their creator who sunk into the background, the tigers were described as “bright topaz denizens”. The tigers were energetic and free to “prance” or run around in the jungle, and in their creator’s imagination. The tigers were created bright, like “topaz”, and they inhabited a world that is green. The “bright topaz denizens of green” evoke a mental image of majestic tigers not bound by the whims of another being. They are in their natural environment. The tigers are conceived as inherently male, they are chivalric, hence tied to the long tradition of male authority and power. However, their “chivalric certainty” is a representation of the power envisioned by Aunt Jennifer for herself. This idea is then contrasted with Aunt Jennifer’s reality where she in turn was dominated by male superiority.

Question 2.
Why do you think Aunt Jennifer’s hands are “fluttering” through her wool in the second stanza? Why is she finding the needle so hard to pull?
Answer:
Aunt Jennifer worked with a piece of wool, stitching patterns into a tapestry. Her fingers fluttered to create the beautiful image of the tigers. She expressed her desires by creating the tigers. She found it difficult to express her feelings, repressed by the weight of marriage, gender roles, and a dominating society. “Uncle’s wedding band” is representative of the patriarchal society she lived in. The weight of the ring was not something she enjoyed as the band is described to sit ‘heavily’ on her hand and kept her from the only mode of expression she had, her needlepoint.

Question 3.
What is suggested by the image “massive weight of Uncle’s wedding band”?
Answer:
The struggle for existence in a harsh world, the deep conflicts of bondage and freedom and gender conflict is portrayed through the use of the evocative image. The genders are polarised. Aunt Jennifer was victimized by the absent Uncle, represented only by his wedding band, while he is representative of the oppression of custom and law.

Question 4.
Why is Aunt Jennifer terrified in the third stanza?
Answer:
In the last stanza, the reader is told that “the tigers in the panel she made/Will go on prancing, proud and unafraid” even after Aunt Jennifer was dead. This showed her fear. The tigers represent her spirit and how she would like to live while her hands, folded even in death, represent the reality of her life.

Question 5.
What are the ordeals Aunt Jennifer is surrounded by? Why is it significant that the poet uses the word “ringed”? What are the meanings of the word “ringed” in the poem?
Answer:
The word “ringed” has a double association. It indicates not only the ring that “sits heavily” on her hand, but the difficulties in her life that would continue to surround her.

Even in death, she is seen to conform to the patriarchal society in which she lived. The ring on her finger symbolised the weight she had to bear, dead or alive. Just as she created and controlled her needlework, society and gender roles created and controlled her.

Question 6.
Why do you think Aunt Jennifer created animals that are so different from her own character? What might the poet be suggesting, through this difference?
Answer:
Aunt Jennifer created an alternative world of freedom, one which she could not inhabit otherwise. The tigers of her creation represented her suppressed desires and her ambition. She was victimised, and stifled in marriage, by the absent figure of the Uncle, represented only by his wedding band. She escaped her reality through her creation. The poet presents an ironic image of a contrast between the common perception of animals as being brutal and of men being humane. Here, the ‘brutal’ tiger represents freedom while the ‘civilised’ man is exposed as the oppressor.

Question 7.
Interpret the symbols found in this poem.
Answer:
Adrienne Rich uses a number of similes and symbols in the poem to convey her theme. The tigers, of course, symbolise the freedom of spirit which Aunt Jennifer dreams of attaining but never achieves except in her dreams and her art. Aunt Jennifer represents of her gender rather than any one individual.

The tigers are symbolic of the true nature of the freedom that a woman’s soul represents. They also display in art the values that Aunt Jennifer must repress or displace in life: strength, assertion, fearlessness and fluidity of motion. The image of the tiger is both inspiring and destructive. And the poem’s conclusion celebrates the animal images as a kind of triumph, transcending the constraints of their maker’s life.
The word ‘ringed’ has a double connotation—indicating not only the ring that “sits heavily” on her hand, but the difficulties in her life that will continue to surround her.

Question 8.
Do you sympathise with Aunt Jennifer? What is the attitude of the poet towards Aunt Jennifer?
Answer:
As a reader, one sympathises with Aunt Jennifer. She aspired for a greater future and a greater standing for her generation. Her mind was liberated from the cloistered association with her sex, but the figure of Aunt Jennifer never got to see women standing strong and proud. In the end, Adrienne Rich showed that Aunt Jennifer represented every woman of her time. Ironically enough, she rebels using the oppressor’s own language to feel a sense of triumph. Overwhelmed by gender roles, and tom between rebellion, the need for expression, and society, Aunt Jennifer expressed her fears and desires through the exotic images of tigers, transcending her dreams and ambitions.

Aunt Jennifer’s Tigers Extra Questions and Answers

Aunt Jennifer’s Tigers Short Answer Questions

Question 1.
What are the characteristics of the tigers?
Answer:
The tigers have a striking appearance as they are described as “bright topaz”. They are energetic and prance about. They enjoy their freedom and hence run across the screen. The majestic tigers are not dictated by the whims of others. They are fearless and chivalrous. The elegant tigers are confident of themselves.

Question 2.
What do you learn about Aunt Jennifer?
Answer:
Aunt Jennifer was a weak woman with fluttering fingers. She was terrified of Uncle and found it difficult to manoeuvre the needle. Thus, implying that she was oppressed by a burdensome marriage where she was subjugated by Uncle.

Question 3.
What does Aunt Jennifer’s creation of the tigers symbolize?
Answer:
Aunt Jennifer’s creation of the tigers symbolizes her desires. Her fingers flutter to create the beautiful image of the tigers. By creating those tigers, she lets loose her inner aspirations. The wedding band sits “heavily” on her hand and keeps her from the only sense of expression she has—her needlepoint.

Question 4.
What does Aunt Jennifer’s death signify?
Answer:
In the last stanza of the poem, the poet gives us a surprisingly truthful look at the reality and the end of Aunt Jennifer and women in her position all over the world. Aunt Jennifer is a subjugated even in death; she must conform to the norms of the patriarchal society. The ring around her finger symbolizes the weight she must bear dead or alive.

Question 6.
What is the theme of the poem?
Answer:
“Aunt Jennifer’s Tigers” clearly reflects the gender struggle that women across the world are subject to. It is a feminist poem in which the poet criticizes the male-dominated world. Aunt Jennifer is left no option than to create an alternate world of freedom. Aunt Jennifer is a woman trapped by the social and cultural expectations and demands of her time.

Question 7.
Who do you think is the speaker of the poem? Why do you say so?
Answer:
The speaker of the poem is the niece; the word “Aunt” shows her relationship with the speaker. The point of view here would seem to be that of a woman, indicating that the speaker is the niece of Aunt Jennifer’s. The niece voices a woman’s struggles with expression, rebellion, and a society where power is defined as masculine. The poem deals with a woman’s representation of Aunt Jennifer’s dreams, reality and the future.

Question 8.
Interpret the following symbols found in this poem.
(a) tigers
(b) Aunt
(c) embroidery
(a) The tigers symbolize the freedom of spirit which Jennifer dreams of attaining but never achieves except in her dreams and her art.
(b) Aunt Jennifer is symbolic of women as a whole rather than one individual.
(c) Aunt Jennifer’s embroidery may exist forever as the work that she leaves behind; in life, she was nothing like the tigers in her embroidery.

Aunt Jennifer’s Tigers Value Based Question

Question 1.
How does the poet advocate gender sensitisation in the poem?
Answer:
The poem reflects the gender struggle; Adrienne Rich criticizes the male-dominated world for terrifying and oppressing women as symbolized by Aunt Jennifer, leaving her with no alternative but to create an alternate world of freedom for herself with her sewing. The embroidering of tigers on the panel, her only form of expression, underlines a woman’s struggles with expression, rebellion, and a society where power is defined as masculine. The poet depicts the pain of a woman who is living with a husband who dominates her. Her hidden, vibrant inner life is in sharp contrast to the outer image of the terrified, trapped woman.

The poem is almost a tragedy relating the plight of women trapped in an unhappy marriage. The poet makes her stance clear by using the figure of independent and fearless tigers as a telling symbol of an ideal that women like Aunt Jennifer seek to approximate. Adrienne Rich yearns for freedom and equality for all women.

Give examples from the poem of the following poetic devices.

Alliteration
“fingers fluttering”
“chivalric certainty”

Symbols
Aunt Jennifer
Tigers
Embroidery
wedding band