Light & Optics MCQs with Answers

Which of the following has the longest wavelength?

• A.X-rays
• B.Ultraviolet rays
• C.Radio waves
• D.Gamma rays

Which type of lens is thicker at the centre than at the edges?

• A.Concave lens
• B.Cylindrical lens
• C.Convex lens
• D.Plano-concave lens

Which phenomenon of light is responsible for the propagation of light through optical fibers?

• A.Scattering
• B.Refraction
• C.Diffraction
• D.Total internal reflection

Compared to the object, real images formed by a lens are always _?

• A.Inverted
• B.Erect
• C.Same size
• D.Magnified

Butter paper is _ material because it scatters light.

• A.Transparent
• B.Opaque
• C.Translucent
• D.Reflective

The sky appears blue because ?

• A.of scattering of light by dust particles and air molecules
• B.shorter wavelengths (blue) are scattered more than longer wavelengths (red)
• C.of reflection of ocean water into the atmosphere
• D.Both A and B

Reflecting prisms usually work on the principle of total ?

• A.Internal Reflection
• B.External Reflection
• C.Internal Refraction
• D.Dispersion

The resolving power of a telescope depends on ?

• A.Diameter of objective lens
• B.Focal length of eyepiece
• C.Magnification power
• D.Length of the telescope tube

The momentum of a moving photon is:

• A.h / λ
• B.h × λ
• C.λ / h
• D.h² / λ

When the angle of refraction is 90° and the refractive index for water is 1.33, the critical angle is ?

• A.48.8°
• B.42.5°
• C.52.4°
• D.45.0°