CBES Board Class 12 MCQ Quiz Hub

1. The idea of secondary wavelets for the. propagation of a wave was first given by
Newton
Huygens
Maxwell
Fresnel

2. Light propagates rectilinearly, due to
wave nature
wavelengths
velocity
frequency

3. Which of the following is correct for light diverging from a point source?
The intensity decreases in proportion with the distance squared.
 The wavefront is parabolic.
The intensity at the wavelength does not depend on the distance.
None of these.

4. The refractive index of glass is 1.5 for light waves of X = 6000 A in vacuum. Its wavelength in glass is
2000 Å
 4000 Å
1000 Å
3000 Å

5. The phenomena which is not explained by Huygen’s construction of wavefront
reflection
diffraction
 refraction
origin of spectra

6. A laser beam is used for locating distant objects because
it is monochromatic
it is not chromatic
it is not observed
it has small angular spread.

7. Two slits in Young’s double slit experiment have widths in the ratio 81 :1. The ratio of the amplitudes of light waves is
1/0/1900 3:01
1/0/1900 3:02
1/0/1900 9:01
1/0/1900 6:01

8. When interference of light takes place
energy is created in the region of maximum intensity
energy is destroyed in the region of maximum intensity
Conservation of energy holds good and energy is distrubuted
Conservation of energy does not hold good

9. To observe diffraction, the size of the obstacle
should beX/2, where X is the wavelength.
should be of the order of wavelength.
has no relation to wavelength.
should be much larger than the wavelength.

10. The velocity of light in air is 3 * 108 ms-1 and that in water is 2.2 * 108 ms” . The polarising angle of incidence is
45°
50°
53.74°
63

11. An optically active compound
rotates the plane of polarised light
changes the direction of polarised light
does not allow plane polarised light to pass through
 none of these