11th class (Fsc) Physics unit 9 MCQs
26. Example of a thin film is:
a. Concave lens
b. Soap bubble
c. Glass plate
d. Convex lens
27. When Newton’s Rings are seen through the transmitted light, then the central spot is:
a. Bright
b. Dark
c. Red
d. Blue
28. Newton’s rings are formed due to phenomenon of:
a. Polarization of light
b. Diffraction of light
c. Total internal reflection
d. Interference of light
29. Newton’s rings are formed as a result of:
a. Diffraction
b. Interference
c. Polarization
d. Dispersion
30. Michelson’s interferometer can be used to find the:
a. Velocity of sound
b. Velocity of light
c. Wavelength of sound
d. Wavelength of light
31. When one mirror of a Michelson interferometer is moved a distance of 0.5mm, 2000 fringes are observed. The wavelength of light used is:
a. 500cm
b. 5000m
c. 2000 Ao
d. 5000 Ao
32. In Michelson interferometer to switch the strings from bright to dark, the mirror should be displaced by:
a. 2/λ
b. 4/λ
c. λ
d. 3/λ
33. In a Michelson interferometer by moving the mirror through a distance of 4/λ. The path difference changes by:
a. λ/4
b. λ/2
c. 2λ
d. λ
34. Bending of light around the edges of an obstacle is called:
a. Interference
b. Refraction
c. Diffraction
d. Polarization
35. Transverse waves are distinguish from longitudinal waves by the:
a. Reflection
b. Interference
c. Polarization
d. Diffraction
36. A typical diffraction grating has certain number of lines per centimeter whose range is:
a. 400 to 500
b. 40 to 50
c. 4000 to 5000
d. 400 to 5000
37. If ‘N’ is number of lines ruled on the grating having length “L” then grating element ‘d’ isgiven by:
a. L/N
b. N/L
c. N/2L
d. 2N/L
38. A glass grating has 5000 lines /cm then grating element will be:
a. 2×10-3m
b. 2×10-6m
c. 2×10-7m
d. 2×10-4m
39. Wavelength of X-rays is of the order of:
a. 10-10m
b. 10-8m
c. 10-4m
d. 10-5m
40. The wavelength of X-rays is of the order of:
a. 10-2m
b. 10m
c. 10cm
d. 10-10m
41. Which phenomenon of light proves that light waves are transverse in nature?
a. Diffraction
b. Refraction
c. Polarization
d. Reflection
42. The phenomenon of polarization of light reveals that sun light is:
a. Electromagnetic waves
b. Longitudinal waves
c. Monochromatic waves
d. Transverse wave
43. Light waves are:
a. Stationary waves
b. Longitudinal waves
c. Mechanical waves
d. Transverse waves
44. To distinguish between transverse and longitudinal wave is used:
a. Polarization
b. Refraction
c. Diffraction
d. Interference
45. Which one of the following cannot be polarized?
a. T.V waves
b. Ultra violet rays
c. Sound waves
d. Radio waves
46. Sound waves cannot be:
a. Diffracted
b. Reflected
c. Polarized
d. Refracted
47. The process of confining the beam of light to vibrate in one plane is called:
a. Polarization
b. Interference
c. Total internal reflection
d. Diffraction
48. Longitudinal waves do not exhibit:
a. Polarization
b. Reflection
c. Diffraction
d. Refraction
49. The blue color of sky is due to:
a. Polarization
b. Diffraction
c. Scattering
d. Reflection
50. Which is not Optically active:
a. Water
b. sugar
c. Sodium chlorate
d. Tartaric acid
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