Prism theory and Dispersion of light MCQs
Q1: The critical angle between an equilateral prism and air is 45. If the incident ray is perpendicular to the refracting surface, then
a) It is reflected totally from the second surface and emerges perpendicular from the third surface.
b) It gets reflected from second and third surfaces and emerges from the first surface
c) It keeps reflecting from all the three sides of the prism and never emerges out
d )After deviation, it gets refracted from the second surface
Answer: (a) It is reflected totally from the second surface and emerges perpendicular from the third surface.
Q2: Which ray is least deviated by a prism?
a) Violet ray
b) Green ray
c) Red ray
d) Yellow ray
Answer: (c) Red ray
Q3: A prism (μ=1.5) has a refracting angle of 300. The deviation of a monochromatic ray incident normally on its one surface will be
a) 180 36’
b) 200 30’
c) 180
d) 190 30’
Answer: (a) 180 36’
Q4: The angle of the prism is equal to the angle of minimum deviation for a prism of refractive index 1.5. What is the value of the angle of the prism?
a) 410
b) 820
c) 620
d) 310
Answer: (b) 820
Q5: The dispersive power of prism depends upon
a) The shape of the prism
b) The material of the prism
c) The angle of the prism
d) Height of the prism
Answer: (b) The material of the prism
Q6: When white light passes through the achromatic combination of prism, then what is observed
a) Dispersion
b) Deviation
c) Dispersion and deviation
d) None of the above
Answer: (b) Deviation
Q7: For a wavelength l the dispersion of the medium is D, then the dispersion for the wavelength 2l will be
a) D/8
b) D/2
c) 2D
d) D
Answer: (a) D/8
Q8: The refractive angle of a prism for a monochromatic light is 600 and refractive index is √2. For minimum deviation, the angle of incidence will be
a) 600
b) 450
c) 300
d) 750
Answer: (b) 450
Q9: The dispersive power will be maximum for
a) Flint glass
b) Crown glass
c) Mixture of glass
d) None of these
Answer: (a) Flint glass
Q10: When white light is passed through a hollow prism then there is
a) no dispersion and no deviation
b) Only dispersion
c) Only deviation
d) Both dispersion and deviation
Answer: (a) no dispersion and no deviation