## Questions from Physics Viva

1. What happens to the resistivity of a wire when it is doublefolded?
2. How does the resistance of a wire depend on its dimensions?
3. 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?
4. Why constantan or manganin wires are used for making the resistance coils in resistance box?
5. What is a standard resistance?
6. What are the characteristics of a standard resistance?
7. What are the precautions to be observed while doing electricity experiments in general?
8. What is a galvanometer?
9. What is the resistance of an ideal ammeter?
10. Why is ammeter always connected in series and voltmeter always connected in parallel?
11. How can we convert a galvanometer into an ammeter or a voltmeter?
12. What is shunt?
13. What is AVO meter?
14. What is the effect of temperature on the resistance of a conductor?
15. Why does the resistance of a conductor increases with temperature, whereas that of a semiconductor decreases with temperature.
16. What is conductance?
17. What are non ohmic devices? give an example.
18. What are superconductors?
19. Define emf
20. Why emf is said to be a misnomer?
21. What happens if the battery used in the primary circuit of a potentiometer has less emf compared to the emf of the cell used in the secondary circuit?
22. If you find that the galvanometer reading is shaky, what error can you expect?
23. What do you mean by figure of merit of a galvanometer?
24. Why a moving coil galvanometer is called so?
25. What is the principle of a galvanometer?
26. What is parallax? How is it removed?
27.  Define dispersion of light. Give its cause.
28.  Show dispersion of white light into seven colours.
29. Define lateral displacements and give the factor on which it depends.
30. Define critical angle and deduce the relation between refractive index and critical angle.
31. Explain U-V graph in case of image formation in a convex lens.
32. Distinguish between primary and secondary cell. (give two differences)
33.  How does rheostat act as a variable resistor, potential divider? (draw a diagram)
34. What a non inductive coil? Give one special feature of non inductive coil?
35. Draw neat and label diagram of leclanche cell.
36. Write chemical equation in Daniel cell.
37. Why is the emf of auxiliary battery greater than the emf to be measured?
38. Why are standard resistances made up of constantan and Manganin?
39. Define figure of merit and give it is S.I unit.

Categories: CBSE Physics, Physics Practical Help, Question Bank   Tags:

## Viva help for Optics Experiments

1. Define refractive index.
2. WHat is the least value of refractive index possible?
3. What can you infer if someone says that he has a medium of refractive index less than one?
4. Define focus.
5. Define pole of a spherical mirror.
6. Define optic centre.
7. What is spherical abberration?
8. WHat is chromatic abberration?
9. What is the focal length of a plane mirror?
10. How will you distinguish between a plane mirror, concave mirror and a convex mirror without feeling its surface with your hand?
11. Under what conditions can a plane mirror for a real image?
12. What are the differences between convex lens and concave lens?
13. What is dispersion?
14. Why a glass slab does not produce dispersion whereas a prism does?
15. Define refractive angle of the prism.
16. What is parallax?
17. What is index correction?
18. How is parallax removed?
19. What are the practical uses of a concave mirror?
20. Why a concave mirror is considered better as a makeup mirror?
21. Why the reflectors used in search lights are paraboloidal and not concave?
22. Distinguish real image and virtual image.
23. Why mirrors are silvered on the back surface?
24. Why a convesx mirror is preferred as the rear view mirror of vehicles?
25. What is the principle on which the working of a simple microscope is based?
26. Define power of a lens.
27. Define angle of deviation
28. What are the factors on which the lateral displacement produced by a glass slab depend?
29. Define critical angle for a pair of media
30. What is total internal reflection?
31. What are the applications of total interna reflection?
32. What is angle of minimum deviation?
33. What are the factors on which the deviation produced by a prism depends
34. What is the cause of dispersion?
35. Why atravelling microscope is called so?

Categories: Physics Practical Help   Tags:

## Part -2 (Electricity Based Experiments :: Viva)

1. What is Ac?
2. WHat is DC?
3. Distinguish unidirectional current and direct current.
4. Define RMS value of AC.
5. What do you mean by frequency of AC?
6. Why the power supply to our houses are AC and not DC?
7. What are the advantages of AC over DC?
8. What is a choke coil?
9. WHy a choke coil is considered better than a resistor to regulate AC?
10. What is an electromagnet?
11. What is resonance?
12. What is the use of sound box in a sonometer?
13. Why can’t we use a transformer in dc circuits?
14. WHy ac transmitted to long distance are at very high voltages?
15. What is electromagnetic induction?
16. State Faraday’s laws of electromagnetic induction.
17. Why Michael Faraday is called the father of electricity though he was not the one who discovered electricity?
18. What is damping?
19. What are eddy currents?
20. State Lenz law.

Categories: Physics Practical Help, Question Bank   Tags:

## Viva Voce Questions from OHM’S LAW, METRE BRIDGE, POTENTIOMETER, GALVANOMETER AND OTHER EXPERIMENTS FROM ELECTRICITY AND MAGNETISM

1. What happens to the resistivity of a wire when it is doublefolded?
2. How does the resistance of a wire depend on its dimensions?
3. 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?
4. Why constantan or manganin wires are used for making the resistance coils in resistance box?
5. What is a standard resistance?
6. What are the characteristics of a standard resistance?
7. What are the precautions to be observed while doing electricity experiments in general?
8. What is a galvanometer?
9. What is the resistance of an ideal ammeter?
10. Why is ammeter always connected in series and voltmeter always connected in parallel?
11. How can we convert a galvanometer into an ammeter or a voltmeter?
12. What is shunt?
13. What is AVO meter?
14. What is the effect of temperature on the resistance of a conductor?
15. Why does the resistance of a conductor increases with temperature, whereas that of a semiconductor decreases with temperature.
16. What is conductance?
17. What are non ohmic devices? give an example.
18. What are superconductors?
19. Define emf
20. Why emf is said to be a misnomer?
21. What happens if the battery used in the primary circuit of a potentiometer has less emf compared to the emf of the cell used in the secondary circuit?
22. If you find that the galvanometer reading is shaky, what error can you expect?
23. What do you mean by figure of merit of a galvanometer?
24. Why a moving coil galvanometer is called so?
25. What is the principle of a galvanometer?

Categories: Physics Practical Help   Tags: