Physics Viva Question

What was the experiment allotted to you?

1. Tell me the principle of a potentiometer?

2. What is internal resistance?

3. What are the factors affecting internal resistance?

4. How does the internal resistance change if we increase the area of electrodes?

5. What will happen to internal resistance if we increase the temperature?

6. How does the Resistance of a conductor vary with temperature?

7. What is relaxation time?

8. Why does the relaxation time decrease with an increase in temperature?

9. Define potential gradient of a potentiometer.

10. How does the sensitivity of a potentiometer vary with potential gradient and Why?

11. Why are the resistances used in a resistance box is like 1,2,2,5,10,20,20,50,100,200,200,500,1000,2000,2000,5000 etc?

12. Ans: In this arrangement all natural numbers upto 10000 ohms (and above) can be realized. 1, 2, 2+1=3,2+2=4,5,5+1=6,5+2=7,5+2+1=8,5+2+2=9 etc

13. Why wire is double folded in resistance box?

14. ANS. This is not correct. If it is to be coiled, it should be done as in Q1. Normally the wire is stretched on a half meter scale and fixed with terminals (or arranged in some other manner) If you feel that the wire need to be coiled, then take care to avoid the magnetic effect.

Optics

Question.1: Define sign convention. Question.2: Define a spherical mirror.

Question.3: What is spherical lens?

Question.4: What is ‘Index Error’? Question.5: Define spherical aberration.

Question.6: How is spherical aberration is removed? Question.7: Why is mirror silvered (mercury polished) at the back surface?

Question.8: What is the principal focus of a lens? Question.9: Define ‘Chromatic Aberration’.

Question.10: Do the power of a lens depend upon its aperture? Question.11: What is angle of deviation?

Question.12: Tell the factors on which ‘angle of deviation’ depends? View Answers

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