## Class 12 Physics MCQs Wave Optics for JEE/NEET

Here, you will get Class 12 Physics MCQ of Chapter 10 Wave Optics for cracking JEE and NEET/AIIMS. By solving these MCQs of Class 12 Physics Chapter 10 Wave Optics, you will get the confidence to crack JEE or NEET. Practice MCQ Questions for Class 12 Physics with Answers on a daily basis and score well in exams.

## Wave Optics Class 12 MCQs Questions with Answers

What happens to the interference pattern the two slits S1 and S2 in Young’s double experiment are illuminated by two independent but identical sources?
(a) The intensity of the bright fringes doubled
(b) The intensity of the bright fringes becomes four times
(c) Two sets of interference fringes overlap
(d) No interference pattern is observed

Answer: (d) No interference pattern is observed

Two sources of light are said to be coherent when both give out light waves of the same
(a) amplitude and phase
(b) intensity and wavelength
(c) speed
(d) wavelength and a constant phase difference

Answer: (d) wavelength and a constant phase difference

When a polaroid is rotated, the intensity of light varies but never reduces to zero. It shows that the incident light is
(a) unpolarised
(b) completely plane polarised
(c) partially plane polarised
(d) None of the above

The intensity of light emerging from the two slits, in Young’s experiment is in the ratio 1 : 4. The ratio of,the intensity of the minimum to that of the consecutive maximum will be
(a) 1 : 4
(b) 1 : 9
(c) 1 : 16
(d) 2 : 3

Light takes 10-10 to cross a glass slab. What is the thickness of the glass slab?
(a) 2 cm
(b) 3 cm
(c) 2.5 cm
(d) 3.5 cm

The application of Doppler effect are
(a) Doppler spectrometer
(c) Doppler velocimeter
(d) All of these

Interference pattern is obtained on a screen due to two identical coherent sources of monochromatic light. The intensity of the central bright fringe is 1. When one of the sources is blocked, its intensity becomes I0. The intensity in two situations is related as
(a) I = 2I0
(b) I = I0
(c) I = 4I0
(d) I = 3I0

In Young’s Double Slit experiment using sodium light (λ = 5898 Å), 92 fringes are seen. If green colour (5461 Å) is used, how many fringes will be seen?
(a) 62
(b) 99
(c) 67
(d) 85

Polaroid glasses is used in sun glasses because
(a) It reduces the light intensity to half on account of polarization
(b) It is fashionable
(c) It has good colour
(d) It is cheaper

Answer: (a) It reduces the light intensity to half on account of polarization

The theory of expanding universe is confirmed by the observation of the spectral lines of the star, which shows
(a) green shift
(b) red shift
(c) violet shift
(d) yellow shift

Poisson’s bright spot was discovered by
(a) Fresnel
(b) Rayleigh
(c) Poisson
(d) Fraunhoffer

The condition for observing Fraunhoffer diffraction from a single slit is that the light wavefront incident on the slit should be
(a) spherical
(b) cylinderical
(c) plane
(d) none of these

The minimum value of the refractive index is
(a) zero
(b) 1
(c) less than 1 but not zero
(d) more than 1

Answer: (c) less than 1 but not zero

The refractive index of diamond is about
(a) 1
(b) 1.42
(c) 2.42
(d) 4.24

A monochromatic light is refracted from air into a glass of refractive index µ. The ratio of the wavelengths of the incident and the refracted waves is
(a) 1 : µ
(b) 1 : µ²
(c) µ : 1
(d) µ² : 1

Two waves of the same frequency and same intensity are super impossed in the same phase. The intensity of the resultant wave at the Central point will be
(a) equal to that of the individual wave.
(b) 3 times that of individual wave.
(c) 2 times that of individual wave.
(d) 4 times that of individual wave.

Answer: (d) 4 times that of individual wave.

The frequency of e.m. wave which is best suited to observe a particle of radius 3 × 10-4 cm is of the order of
(a) 1014
(b) 1013
(c) 1012
(d) 1015

The principle of super position in wave motion tells that in a motion in which two or more waves are simultaneously producing their displacement in a particle, then the resultant
(a) amplitude is the sum of the individual amplitudes.
(b) amplitude is the difference of the individual amplitudes.
(c) displacement is the vector sum of the individual displacements.
(d) none of these

Answer: (c) displacement is the vector sum of the individual displacements.

If n represents the order of a half period zone, the area of this zone is nearly proportional to nm. where m is equal to
(a) 1
(b) 1/2
(c) 2
(d) zero

Images of a distant lamp seen through a fire cloth rotate on rotating the cloth. This is due to the phenomenon of
(a) interference
(b) diffraction
(c) polarisation
(d) scattering

Light takes 10-10 to cross a glass slab. What is the thickness of the glass slab?
(a) 2 cm
(b) 3 cm
(c) 2.5 cm
(d) 3.5 cm

Out of the following Statements which is not correct?
(a) When unpolarised light passes through Nicol’s prism, the emergent light is elliptically polarized
(b) Nicol’s prism works on the principle of double refraction and T.l.R.
(c) Nicol’s prism can be used both the produce and analyse polarized light
(d) Calcite and Quartz are both double refracting crystal

Answer: (a) When unpolarised light passes through Nicol’s prism, the emergent light is elliptically polarized

A phase difference of 5π corresponds to a path difference (in terms of λ) of
(a) 5λ
(b) 10λ.
(c) 5λ/2
(d) 2λ

A person cannot see object clearly beyond 50 cm. The pow er of the lens to correct his vision is
(a) +0.5 dioptre
(b) -0.5 dioptre
(c) -2 dioptre
(d) +2 dioptre