Physics XI Karachi Board MCQs Chapter 9

Chapter 9 - Wave Aspect of Light
1. Light waves __________.

(Require air or another gas to travel through, require an electric field to travel through, require a magnetic field to travel through, can travel through a perfect vacuum)

2. The blue colour of the sky is due to due to fact that __________.

(Red light is absorbed, blue colour is preferentially scattered, red light is preferentially scattered, this is the natureal colour)

3. The wavelength 10000 A° belong to __________.

(Infra red spectrum, Ultra violet spectrum, visible range, green light)

4. Monochromatic green light has a wavelength of 520 nm in air. The wavelength of this light inside glass of refractive index 1.5 is approximately.

(300nm, 340nm, 520nm, 780nm)

5. The property of light waves thath leads to the phenomenon of colour is their __________.

(Velocity, Amplitude, Quality, Wavelength)

6. If Plank’s constant h = 6.625 x 10-34 J/Hz. The energy associated with light with a wavelength of 160nm is __________.

(1.24 x 10-18 J, 1.88 x 10-18 J, 1.24 x 10-15 J, 1.24 x 10-15 J)

7. __________ proposed electromagnetic wave theory.

(Fresnel, Huygen, Maxwell, Fraunhoffer)

8. Two light waves meet at time when one has the instantaneous amplitude A and the other has the instantaneous amplitude B. Their combined amplitude is __________.

(A + B, between A + B and –(A + B), A – B, Indeterminate)

9. Maxwell based his theory of electromagnetic waves on the hypothesis that a changing electric field gives rise to __________.

(An electric current, stream of electrons, A magnetic field, longitudinal waves)

10. __________ of the following phenomenon cannot be explained by the wave theory of light.

(Refraction, Interference, Photoelectric, Polarization)

11. In the complete electromagnetic spectrum __________ of the following has least frequency.

12. The number of fringes passing through a reference point, if the moveable mirror of Michlson’s interferometer is moved by 0.08 mm, when the wavelength of light used is 5800 A°, are __________.

(275, 276 250, 2.75)

13. __________ of the following demonstrates the transverse nature of light waves.

(Interference, Polarization, Diffraction, Refraction)

14. The locus of all points in the same state of vibrations is known as __________.

(Half period zone, a half wave zone, a wave front, none of thse)

15. __________ is invalid for a photon.

(Its mass is h2n2, it has zero rest mass, all its energy is K.E, its momentum is hn/c)

16. __________ of the following is not a property of light waves.

(they transfer energy from one place to another, They can travel through vacuum, They are transverse waves, They travel at the same speed through glass and water)

17. The phenomenon of interference of light was first demonstrated by __________.

(Newton, Einstein, Thomas Young, Michelson)

18. __________ of the following is not associated with light waves.

(Transmission of energy, Interference, Diffraction, Longitudinal Vibrations)

19. Formation of colour in a thin film of oil is due to __________.

(Interference of light waves, diffraction of light waves, Scattering of light rays, Dispersion of light rays)

20. Newton’s rings are formed due to the phenomenon of __________.

(Reflection, Refraction, Diffraction, thin film interference)

21. Interferometer measures __________.

(Velocity of light in gases, wavelength of monochromatic light, thickness of very thin objects, illuminating power of light)

22. __________ of the following is not true for interference of light.

(The two waves should be of same amplitude, the two waves should be phase coherent, the two waves should travel in the opposite direction through the medium, the two waves should be monochromatic)

23. Two monochromatic waves of same wavelength are travelling through a medium. They can interfere destructively. Provided their path difference is __________.

(2l, l, 5/2 l, 5l)

24. Double slit arrangement is suggested by Young in order to obtain __________.

(monochromatic light, phase coherence, constructive interference, destructive interference)

25. In Young’s double slit arrangement, the bright fringes obtained are __________.

(Of uniform intensity, of non uniform width, coloured, circular)


26. For constructive interference the path difference should be __________.

(Zero or integral multiple of wavelength, only integral multiple of wavelength, zero or multiple of wavelength, odd multiple of wavelenght)

27. The two light waves can interference destructively if __________.

(They reach a point in phase, they reach a point out of phase by p radian, they are traveling through a medium in opposite direction, none of these is true)

28. Newton’s rings can be obtained by using a __________.

(Plano convex lens of small focal length, plano convex lens of very large focal length, concave lens of large focal length, flat glass slab)

29. In Newton’s rings the central angle is __________.

(Always bright, always dark, can be bright or dark, of blue colour)

30. The conditions for the production of constructive and destructive interference are reversed due to the fact that on striking the thin film __________.

(Two rays of splitted light under go phase change of 180°, One of two rays of splitted light undergo phase change of 180°, light is diffracted, light is polarized)

31. When electromagnetic waves strike the boundary of denser medium they are __________.

(Reflected, in phase, Reflected out of phase by 180°, reflected, they are completely abosrbed)

32. In Michelson interferometer semi silvered mirror is used to obtain __________.

(Thin film interference, Phase coherence, mono chromatic light, coloured fringe)

33. Diffraction is special type of __________.

(Reflection, Refraction, Interference, Polarization)

34. Fresnel’s type diffraction is observed when __________.

(Only screen is placed at finite distance, Only source is placed at finite distance, Both source and screen are at finite distance, Neither source nor screen is at finite distance)

35. Fraunhoffer’s diffraction is observed when __________.

(Only screen is placed at finite distance, souce is placed at finite distance, neither source nor screen is at finite distance)

36. In Fraunhoffer’s diffraction wave front used is __________.

(Spherical, Circular, Plane, Conical)

37. In diffraction pattern of monochromatic light the bright bands formed are __________.

(Of uniform intensity, of non-uniform intensity, of uniform width, are of different colours)

38. The points of constructive interference of light are __________.

(Always bright, may be bright or dark, always dark, neither bright nor dark)

39. The diffraction observed by diffraction grating can also be termed as __________.

(Single slit diffraction, Double slit Diffraction, Multiple Slit Diffraction, Fresnel’s Diffraction)

40. The grating used to observe, diffraction of visible light can have approximately __________.

(300 lines per cm, 3000 lines per cm, 15000 lines per cm, 30 lines per cm)

41. X-ray diffraction can be observed by using __________.

(Diffraction Grating, Rock salt crystal, Convex lens, Michlsons’s interferometer)

42. The phenomenon of Newton’s rings can be used to check the __________.

(Wavelength of monochromatic light, phase coherence of two sources, flatness of any glass surface, velocity of light)

43. Two sources of light are said to be coherent if __________.

(they produce waves of the same wave length, they have the same amplitude of vibration, they produce waves in the medium simultaneously, they produce waves of the same amplitude)

44. As the order increases, the width of a dark band in diffraction patterns __________.

(Increases, Decreases, Does not change, becomes infinity)

45. The path difference corresponding to a phase difference of p radian is __________.

(2l, l/2, l/4 l)

46. __________ of the following phenomenon can not be explained on the particle nature of light.

(Photo Electric Effect, Compton’s Effect, Pair Production, Interference)

47. Fringe spacing is defined as the distance between two consecutive __________.

(Crests, Bright fringes only, Dark fringes only, Bright or dark fringes)

48. If we narrow the distance between two slits in Young’s experiment the fringes width __________.

(Increases, Decreases, Remains same, becomes zero)

49. When Newton’s rings interference pattern is viewed from above by means of reflected light, the central spot is __________.

(Dark, Multicoloured, Bright, None of these)

50. There are two types of diffraction Fresnel and __________.

(Michelson, De Broglie, Fraun Hofer, Huygens)