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#### Important 2 Mark Creative Questions (New Syllabus) 2020

12th Standard EM

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Physics

Time : 01:00:00 Hrs
Total Marks : 54

Part A

27 x 2 = 54
1. What are induced dipoles.

2. Asphere of charge +Q is fixed. Asmaller sphere of charge +q is placed near the larger sphere and released from rest. The small sphere will move away from large sphere with
a. decreasing velocity & decreasing acceleration.
b. decreasing velocity & increasing acceleration.
c. decreasing velocity &constant acceleration d. increasing velocity & decreasing acceleration
e. increasing velocity & increasing acceleration
Which of the above statement is correct? Explain.

3. Aparallel plate capacitor is charged by a battery after some time, the battery is disconnected and a dielectric slab with its thickness equal to the plate so reparation is insected between the plates. How will
(i) the capacitance of the capacitor
(ii) potential difference between the plates &
(iii) the energy stored in the capacitor the affected?
Qo - charge; Vo - potential difference,
Co - capacitance, Eo- electric field.
U0 - energy spred, before the dielectric slab is inserted.
${ Q }_{ 0 }={ C }_{ 0 }{ V }_{ 0 };\frac { { B }_{ 0 } }{ d } ;{ U }_{ 0 }=\frac { 1 }{ 2 } { C }_{ 0 }{ v }_{ 0 }^{ 2 }$

4. How does the energy stored. in a capacitor change it
(i) after disconnecting the battery, the plates of a charged capacitor are moved faster.
(ii) The battery remaining connected capacitance c∝$\frac{1}{d}$, when plates of capacitor.

5. Define mean free time $\tau$

6. Define the term electric power and circuit its SI unit.

7. How heating effect is used in electrical lamp.Name other lamps which use the heating effected?

8. Why are resistor connected in series and in parallel (i) To increase the resistor of the circuit. the resistor are connected in series.

9. State the elements of Earth's magnetic field.

10. What do you mean by coercivity?

11. Define Current sensitivity?

12. What is magnetic Lorentz force?

13. Write the application of series RLC resonant circut

14. What is waltless current?

15. (i) In which situation is there a displacement current but no conduction current?
(ii) Find the displacement current across the plate of the capacitor whose charging current is 0.25 A.

16. Write the two conditions for total internal reflection.

17. What is spectrum?

18. What will be the effect on interference fringes if red light is replaced by blue light?

19. The image of an object formed by a lens on the screen is not in sharp focus. Suggest a method to get a dear focussing of the image on the screen without disturbing the positions of the object, the lens or the screen.

20. The stopping potential in an experiment on photoelectric effect is 2V. What is the maximum kinetic energy of the photoelectrons emitted?

21. If the intensity of light falling on a metal plate is doubled, what will be the effect on photocurrent and maximum kinetic energy of emitted photoelectrons?

22. What causes the sun to expand?

23. Define Rectification.

24. What is Breakdown voltage?

25. Why ground wave propagation is not suitable for high frequency?

26. What is the use of nano paints?

27. What is the two ways of preparing nano particle?