# 12th Physics Revision Test Model Question Paper 2021-22

12th Physics Revision Test Model Question Paper 2021-22. TN 12th Standard Revision Test Model Question papers download PDF. 12th Samacheer kalvi Guide. 12th All Subject Unit Test All-District Question papers. 12ஆம் வகுப்பு நவம்பர் மற்றும் டிசம்பர் மாத பாடத்திட்டம்). 12th Revision Test Syllabus.

## Part – 1   (15 x 1= 15)

#### Choose the most suitable answer and write the code with the corresponding answer

1. Which charge configuration produces a uniform electric field?
(a) point charge

(b) uniformly charged infinite line

(c) uniformly charged infinite plane

(d) uniformly charged spherical shell

2. Two identical conducting balls having positive charges ql and q2 are separated by a centre to centre distance r. If they are made to touch each other and then separated to the same distance, the force between them will be
(a) less than before

(b) same as before

(c) more than before

(d) zero

3. If the voltage applied on a capacitor is increased from V to 2 V, choose the correct conclusion.
a) Q remains the same, C is doubled

b) Q is doubled, C doubled

c) C remains same, Q doubled

d) Both Q and C remain same

4. A parallel plate capacitor stores a charge Q at a voltage V. Suppose the area of the parallel plate capacitor and the •sta ce oetween the plates are each doubled then which is the quantity that will change?

(a) Capacitance

(b) Charge

(c) Voltage

(d) Energy density

5. A carbon resistor of (47 ± 4.7 ) k  to be marked with rings of different colours for its identification . The colour code sequence will be

a) Yellow – Green – Violet – Gold

b) Yellow – Violet – Orange – Silver

c) Violet – Yellow – Orange – Silver

d) Green – Orange – Violet – Gold

6. A toaster Operating at 240 V has a resistance of 120  Its power is

a) 400 W

b) 2 W

c) 480 W

d) 240 W

7. In Joule’s heating law, when R and t are constant, if the H is taken along the y axis and 12 along the x axis, the graph is

a) straight line

b) parabola

c) circle

d) ellipse

8. A piece of copper and another of germanium are cooled from room temperature to 80 K. The resistance of

a) each of them increases

b) each of them decreases

c) copper increases and germanium decreases

d) copper decreases and germanium increases

9. A circular coil of radius 5 cm and 50 turns carries a current of 3 ampere. The magnetic dipole moment of the coil is nearly

a) 1.0 A m2

b) 1. A m2

c) 0.5 A m

d) 0.8 A m2

10. The vertical component of Earth’s magnetic field at a place 1s equal to the horizontal component. What is the value of angle of dip at this place?

a) 30°

b) 45 °

c) 60 °

d) 90 °

11. A thin insulated wire forms a plane spiral of N = 100 tight turns carrying a current I = 8 m A (milli ampere). The radii of inside and outside turns are a = 50 mm and b = 100 mm respectively. The magnetic induction at the centre of the spiral is
a) 5 µT

b) 7 µT

c) 8 µT

d) l O µT

12. is an instrument used to measure current in an electrical circuit.

a) Ammeter

b)Galvanometer

c)voltmeter

d) none of the above

13. When the current changes from +2A to -2A in 0.05 s, an emf of 8 V is induced in a coil. The co-efficient of self-induction of the coil is

a) 0.2 H

b) 0.4 H

c) O.B H

d) 0.1 H

14. In a transformer, the number of turns in the primary and the secondary are 410 and 1230 respectively. Ifthe current in primary is 6A, then that in the secondary coil is
a) 2 A

b) 18 A

c) 12 A

d) l A

15. A step-down transformer reduces the supply voltage from 220 V to 11V and increase the current from 6 A to 100 A. Then its efficiency is

a) 1.2

b) 0.83

d) 0.9

## Part – 2 (6 x 2 = 12)

#### Answer any six of the Following (Question No. 24 is compulsory)

16. What for an inductor is used? Give so e examples.
17. State Fleming’s right hand rule.
18. Define magnetic flux.
19. State Biot-Savart’s law.
20. Define current density.
21. What is Seebeck effect?
22. Write a short note on superposition principle.
23. Define ‘electric flux’.
24. Define ‘capacitance’. Give its unit.

## Part – 3 (6 x 3 = 18)

#### Answer any six of the Following (Question No. 33 is compulsory)

25. Discuss the basic properties of electric charges.
26. 0btain Gauss law from Coulomb’s law
27. State the applications of Capacitors
28. State and explain Kirchhoff s rules.
29. Give the difference between Coulomb ‘s law and Biot-Savart’s law.
30. What are the properties of bar magnet?
31. Define average value of an alternating current.

32. What are step-up and step-down transformers?
33. An electron moving perpendicular to a uniform magnetic field 0.500 T undergoes circular motion of radius 2.50 mm. What is the speed of electrons?

## Part – 4 (5 x 5 = 25)

#### Answer all the Questions: –

34. A) Explain the construction and working of transformer.

[OR]

B) Mention the various energy losses in a transformer.

35. A) Derive an expression for electrostatic potential due to an electric dipole.

[OR]

B) Explain in detail the construction and working of a Van de Graaff generator.

36. A) Obtain the condition for bridge balance
B) i. State the applications of the Seebeck effect.
ii. Define electrical resistivity.

[OR]

37. A) Calculate the magnetic field inside a solenoid, when
i. the length of the solenoid becomes twice with fixed umber of turns
ii. both the length of the solenoid and number of turns are doubled
iii. the number of turns becomes twice for the fixed length of the solenoid.

[OR]

B) Obtain a relation for the magnetic field at a point along the axis of a circular coil carrying current.

38. A) Dielectric strength of air is 3 x 106 V m-1. Suppose the radius of a hollow sphere in the Van de Graff generator is R = 0.5 m calculate the maximum potential difference created by
this Van de Graaff generator.

[OR]

B) Prove that the total energy is conserved during LC oscillations.

#### 12th Physics Revision Test Model Question Paper 2021-22

 12th Revision Test Model Question Paper 2021-22