#### 12th Standard English Medium Physics Reduced syllabus Two mark important Questions - 2021(Public Exam )

12th Standard

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Physics

Time : 01:00:00 Hrs
Total Marks : 100

2 Marks

50 x 2 = 100
1. What is meant by quantisation of charges?

2. Define ‘Electric field’.

3. (i) Two insulated charged copper spheres A & B of identical size have charges qn and -3qA respectively. When they are brought in contact with each other and then separated. What are the new charges on them?
(ii) When third sphere of some size but uncharged is brought in contact with first and then second and finally removed? What are the new charges.

4. A charge Q μc is placed at the centre of a cube what would be the
(i) flux through one face?
(ii) flux passing through two opposite faces of the cube?
Electric flux through whole cube $\frac { Q }{ { \varepsilon }_{ 0 } }$

5. Represent the variation of electric field due to point charge Q with
a) magnitude of charge Q
b) r and
c) $\frac{1}{r^2}$ where r is the distance of the observation point from the charge. graphically.

6. Two isolated metal spheres A &B have radii R & 2R respectively and same charge q. Find which of the two spheres have greater energy density just outside the surface of the sphere.

7. The graph shows the variation of volatage 'v' across the plates of two capacitors A & Bversus increase of charge 'Q' stored on them. Which of the two capacitors has higher capacitance?
Give reason.

8. Body placed at the centre are shown. Identify the polarity of the charge & draw the electric field lines due to it

9. State microscopic form of Ohm’s law.

10. Define electrical resistivity

11. Define current density.

12. What are free electrons?

13. What is the effective resistance of resistors connected in series

14. The current - voltage graphs for a given metallic at two different temperatures T1 & T2 are shown in figure. The temperature. T2 is greater than temperature T1• State whether statement is true or false. Given reason.

15. Define magnetic dipole moment.

16. What is magnetic permeability?

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

18. What is meant by power transmission?

19. What is meant by Sinusoidal alternating voltage and current? Give its expression

20. Write down the integral form of modified Ampere’s circuital law.

21. Write the uses of Micro waves.

22. State the laws of refraction.

23. Derive the relation between f and R for a spherical mirror.

24. For the same angle of incidence, the angles of refraction in media P, Q and Rand 35°, 25°, 15° respectively. In which medium will the velocity of light be minimum?

25. A proton and an electron have same kinetic energy. Which one has greater de Broglie wavelength. Justify.

26. What is meant by surface barrier?

27. What is photo voltaic cell?

28. Ultraviolet light is incident on two photosensitive materials having work functions W1 and W2 (W1 > W2). In which case will the kinetic energy of the emitted electrons be greater? Why?

29. If the potential difference used to accelerate electrons is tripled, by what factor does the de Broglie wavelength of the electron beam change?

30. What is mean life of nucleus? Give the expression.

31. Which ray has high ionising power? Why?

32. A fusion reaction is more energetic than a fission reaction. Why?

33. What is meant by nuclear fission?

34. Classify the neutrons according to their kinetic energy.

35. What is a reactor core?

36. What is the role of nanostructure in the morpho butterfly wings?

37. Who invented Unimate?

38. What is Cosmology?

39. Obtain the relation between phase difference and path difference.

40. What is a diffraction grating?

41. Discuss polarisation by selective absorption.

42. Mention the types of optically active crystals with example.

43. What are the advantages and disadvantages of using a reflecting telescope?

44. What is meant by constructive interference?

45. Define interference of light.

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

47. Images formed by totally reflected light are brighter than the images formed by ordinary reflected light. Why?

48. Mention any three LED application.

49. What is meant by Biasing?

50. Explain knee voltage