In This Post we are providing Chapter-10 Wave Optics NCERT MCQ for Class 12 Physics which will be beneficial for students. These solutions are updated according to 2021-22 syllabus. These MCQS can be really helpful in the preparation of Board exams and will provide you with a brief knowledge of the chapter.
NCERT MCQ ON WAVE OPTICS
Question 1.
What happens if one of the slits, say S1 in Young’s double , slit experiment-is covered with a glass plate which absorbs half the intensity of light from it?
(a) The bright fringes become less-bright and the dark fringes have a finite light intensity
(b) The bright fringes become brighter and the dark fringes become darker
(c) The fringe width decreases
(d) No fringes will be observed
Answer: (a) The bright fringes become less-bright and the dark fringes have a finite light intensity
Question 2.
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
Question 3.
What is the reason for your answer to the above question?
(a) The two sources do not emit light of the same wavelength
(b) The two sources emit waves which travel with different speeds
(c) The two sources emit light waves of different amplitudes
(d) There is not constant phase difference between the waves emitted by the two sources
Answer: (d) There is not constant phase difference between the waves emitted by the two sources
Question 4.
A single slit diffraction pattern is obtained using a beam of red light What happened the red light is replaced by the blue light?
(a) There is no change in diffraction pattern
(b) Diffraction fringes become narrower and crowded
(d) Diffraction fringes become broader and farther apart
(d) The diffraction pattern disappear
Answer: (b) Diffraction fringes become narrower and crowded
Question 5.
When a polaroid is rotated, the intensity of light varies but never reduces to zero. It shows that the incident light is:
(a) unpolarized
(b) completely plane polarized
(c) partially plane polarized
(d) None of the above
Answer: (c) partially plane polarized
Question 6.
When a polaroid is rotated, the intensity of light does not vary. The incident light may be:
(a) unpolarized
(b) completely polarized
(c) partially plane polarized
(d) None of the above
Answer: (a) unpolarized
Question 7.
In Young’s double slit experiment, a maximum is obtained when the path difference between the interfering waves is (n ∈ l):
(a) nλ
(b) n λ2
(c) (2n + 1) λ2
(d) (2n – 1) λ4
Answer: (a) nλ
Question 8.
For sustained interference, we need two sources which
emit radiations :
(a) of the same intensity
(b) of the same amplitude
(c) having a constant phase difference
(d) None of these
Answer: (c) having a constant phase difference
Question 9.
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
Question 10.
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
Answer: (b) 1 : 9
Question 11.
Poisson’s bright spot was discovered by:
(a) Fresnel
(b) Rayleigh
(c) Poisson
(d) Fraunhoffer
Answer: (c) Poisson
Question 12.
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
Answer: (b) red shift
Question 13.
The application of Doppler effect are:
(a) Doppler spectrometer
(b) Doppler radius
(c) Doppler velocimeter
(d) All of these
Answer: (d) All of these
Question 14.
Which of the following is conserved when light waves interfere?
(a) phase
(b) intensity
(c) amplitude
(d) none of these
Answer: (d) none of these
Question 15.
In Young double slit experiment, a minimum is obtained when the phase difference of the superposing waves, is (n ∈ l):
(a) nπ
(b) (n + 12)π
(c) (2n + 1)π
(d) zero
Answer: (c) (2n + 1)π