NEET Physics Prism and Dispersion of Light MCQs Set A

Question: The angular dispersion produced by a prism

a) increases if the average refractive index increases

b) increases if the average refractive index decreases

c) remains constant whether the average refractive index increases or decreases

d) has no relation with average refractive index

Answer: increases if the average refractive index increases

Question: If a glass prism is dipped in water, its dispersive power

a) decreases

b) increases

c) does not change

d) may increase or decrease depending on whether the angle of the prism is less than or greater than 60º

Answer: decreases

Question:  The refracting angle of a prism is ‘A’, and refractive index of the material of the prism is cot(A/2). The angle of minimum deviation is :

a) 180° – 2A

b) 90° – A

c) 180° – 3A

d) 180° + 2A

Answer: 180° – 2A

Question: By properly combining two prisms made of different materials, it is not possible to have

a) neither dispersion nor average deviation

b) both dispersion and average deviation

c) deviation without dispersion

d) dispersion without average deviation

Answer: neither dispersion nor average deviation

More Questions.....................................

Question: When the incidence angle is equal to the angle of emergence of light from the prism the refracted ray inside the prism

a) becomes parallel to the base of prism

b) becomes perpendicular to the left face of prism

c) becomes perpendicular to the base of prism

d) becomes parallel to the right face of prism

Answer:  becomes parallel to the base of prism

Question:  Light of wavelength 4000 Å is incident at small angle on a prism of apex angle 4°. The prism has n_v = 1.5 and n_r = 1.48. The angle of dispersion produced by the prism in this light is

a) None of these

b) 0.08°

c) 0.2°

d) 0.192°

Answer: None of these

Question: A thin prism P₁ with angle 4° and made from glass of refractive index 1.54 is combined with another prism P₂ made of glass of refractive index 1.72 to produce dispersion without deviation. The angle of prism P₂ is

a) 3°

b) 2.6°

c) 4°

d) 5.33°

Answer: 3°

Question:  A ray of light is incident normally on one refracting surface of an equilateral prism. If the refractive index of the material of the prism is 1.5, then

a) the ray undergoes total internal reflection at second refracting surface

b) the ray emerges normally from the second refracting surface

c) the emergent ray just graces the second reflecting surface

d) the emergent ray is deviated by 60°

Answer:  the ray undergoes total internal reflection at second refracting surface