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Monday, June 19, 2017

AHSEC - Class 12 Question Papers: Physics' 2014

PHYSICS (Theory)
Full Marks: 70

Time: 3 hours
The figures in the margin indicate full marks for the questions

1. Answer the following questions: 1x8=8
  1. Give the dimensions of Tesla.
  2. Show that Weber = Volt x Second.
  3. State Ampere’s circuital law.
  4. Why are infrared waves called heat waves?
  5. State Snell’s law of refraction of light.
  6. Complete the nuclear reaction –
  1. Write down the truth table of NAND gate.
  2. Give one use of solar cell.
2. State Coulomb’s law of electrostatics. Explain it in vector form. 1+1=2

What is electric polarization vector? Define the electric susceptibility. 1+1=2
3. State Ohm’s law of current electricity. Define One Ohm resistance. 1+1=2
Find the equivalent resistance between A and D. 2
4. What do you mean by specific resistance of a conductor? What is its S.I. unit? 1+1=2
What is a potentiometer? Would you prefer a voltmeter or a potentiometer to measure the e.m.f of a battery? 1+1=2
5. Explain how Lenz’s law establishes the law of conservation of energy. 2
6. Describe in brief the concept of displacement current. 2
How does a charge ‘q’ oscillating at certain frequency produce electromagnetic waves? 2
7. State two important differences between interference and diffraction. 2
Two lenses of powers + 5D and – 3D are in contact. Find the focal length of the combination. 2
8. Write down Einstein’s photo electric equation and explain each of its terms. 2
Work function of Caesium is 2.14eV.
  1. Find its threshold frequency.
  2. If its stopping potential is 0.6V, find the wavelength of the incident radiation.
9. Find the wavelength of an electron accelerated through a potential difference of 1 Volt. 2
10. Define 1 Curie unit of radio-activity. What do you mean by ‘half life’? 1+1=2
11. Draw a labeled block diagram of a radio transmitter. 2
12. Apply Gauss’s theorem to calculate the electric field due to an infinite plane sheet of charge. 3
13. Deduce an expression for the capacity of a parallel plate condenser. 3
If, calculate the electric flux through a surface of area 20cm2 in plane. 3
14. Apply Kirchoff’s law of current electricity to establish the condition of a balanced Wheatstone’s bridge. 3
15. Using Ampere’s circuital law, find the magnetic flux density at the centre of a long solenoid carrying current.       3
Describe the working of a moving coil galvanometer. 3
16. Obtain an expression for torque acting on a rectangular coil carrying current placed in a uniform magnetic field.   3
Distinguish among paramagnetic, ferromagnetic and diamagnetic materials qualitatively. 3
17. Deduce the relation for a concave lens. 3
An image is placed 30cm away from a concave lens of focal length 15cm. Find the position, size and nature of the image. 3
18. Find the expression of fringe width for Young’s double slit interference pattern where 2d is the separation between the two coherent sources. 3
Find the value of angle of minimum deviation of a prism [Given]
19. Explain mass defect and binding energy. 3
If, calculate the binding energy of the nitrogen nucleus in. 3
20. What is demodulation? Why is satellite communication necessary for TV signals? 1+1+1=3
What is the basic difference between amplitude modulation and frequency modulation? Discuss the role of ionosphere in radio-wave communication. 1+2=3
21. An inductor of self inductance is connected in series with a non inductive resistor of resistance. A source of e.m.f. Volt is connected in the circuit. Find the 1+2+2=5
  1. Reactance of the coil.
  2. Impedance of the circuit.
  3. Rms voltage drop across the inductor.
Explain briefly with the help of a labeled diagram the basic principle of the working of an a.c. generator. Give two reasons for energy loss in an actual transformer. 3+2=5
22. What are unpolarised and linearly polarised light waves? Establish Brewster’s law. What is the Polaroid? 2+2+1=5
Establish the following relation –
23. Draw a common-emitter amplifier circuit using an n-p-n transistor and explain the amplifier action. Find an expression for a.c. voltage gain. 1+3+1=5

What is photodiode? Explain its working principle. What is a solar cell? 1+3+1=5

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