Viva questions

Unit = 2

1. What is the vector from of ohm’s law?

2. Why constantan, manganin and nichrome are used for making

standard resistances?

3. How can a resistance box offer resistance by taking out the key?

4. What are non inductive resistance coils? How they are made?

5. Why the balance point should be between 35 - 65 cm?

6. Why metre bridge can’t suitable for very small or very large

resistances?

7. Why interconnections in metre bridge are made of thick upper

stripe?

8. Which material is read in making metre bridge is read in making

metre bridge wires?

9. What is the advantage of using Meter Bridge for finding unknown

resistance?

10. What are end in metre bridge?

11. What is the order of resistivity of alloys?

12. What are the two faults in a potentiometer if balance point is not

obtained?

13. Out of 10 wire and 4 wire potentiometer which is better?

14. What is the relation between sensitivity and potential gradient?

15. How can we increase potentiometer’s sensitivity?

16. What will happen to balance point if value of resistance connected

parallel with the cell is increased?

17. What will happen to balancing length if resistance from rheostat is

increased?

18. What is the purpose of using resistance in series with galvanometer?

Does it effects the null point ?

19. Why potentimetre is prefaced for measuring EMF?

20. What will happen to internal resistance on increasing temperature?

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21. What are the constituents of lechlanche and Daniel cell?

22. What is the value of R connected inside the ∞R in resistance box?

23. What is short circuit and open circuit

24. Why it is advised to keep Zn rod out if this cell if not in use?

25. What is the principle of meter bridge and potentiometer ?

26. Why jockey should not be rubbed on the wire ?

OPTICS

SEMI

1. Specialty of Zener diode ?

2. How and why Zener diode is used as voltage regulator ?

1. What is parallax ?

2. What is index correction ?

3. What is chromatic and spherical aberration in lenses .

4. Is the formula R/2 applicable for lenses ?

5. What will happen to power and focal length of lens if it is placed in

water or in a medium of n = 1.5?

6. What changes will you observe in the focal length of a mirror if placed inside water?

7. If a length is cut transverse to it length and along its length, what will

be the changes in focal length and power?

8. What are real and virtual image ?

9. In which quadrant, graph is plotted in case of convex lens and mirror ? what is the shape of the graph in case of convex lens and

concave mirror when graph is platted between u & v, I/u & I/v ?how

it can be obtained from it?

10. What are virtual objects ?is u +ve or –ve

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3. How resistance of diode can be obtained from the graph?

4. What is dynamic resistance?

5. Why a battery of larger value and uA is used in reverse bias ?

6. Which has better mobility ? electrons or holes ?

7. Explain movement of holes?

PRISM

1. What is the cause of dispersion?

EMI, AC

1. Why capacitor blocks DC? What will happen to brightness of bulb if

a dielectric is introduced inside capacitor connected to bulb and AC

source ?

2. Under what conditions inductor will offer zero Resistance?

MISC.

1. What is electrostatic shielding ?

2. What is the direction of area vector?

3. Current is scalar or vector?

4. What is the phase difference between I and V in case of inductor and capacitor.

5. Why choke coil is preferred for controlling currents ?

6. What is the angle of dip and declinition?

7. In which direction magnetic compass will stay if taken to poles ?

8. What is apparent angle of dip?

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𝐵9. How → field lines modified in case of :diamagnetic, paramagnetic and

ferromagnetic

10. What is displacement current?

11. Define refractive index in 7 ways.

12. What is the case of refraction?

13. What is law of malus, brewester law ?

14. Explain huygen’s principle ?

15. What will happen to apparent depth and power if red light is

replaced by violet light?

16. What is the principle of microwave .

17. What is the phase difference between I and V at resonance

18. What is the condition of resonance in cyclotron?

19. Draw resistivity vs temperature plot for metal, semiconductor and

alloy.

20. Define curie law.

21. Define magnetic susceptibility , permeability

22. Why is water a universal solvent, why its dielectric constant is high?

23. What happens to drift velocity if length, area, Potential are increased

individually?

24. What happens to resistance if wire is stretched to make its length ‘n’

times the original?

25. How to find net EMF of 3 cells connected in parallel ?

26. What will happen to balance point if galvanometer and battery is

interchange?

27. If readings of galvanometer are increase which going from A →B ,

these which fault is done by student ? What is the reason if readings

are decreased ?

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