Light & Optics MCQs with Answers

To obtain greater dispersion by a diffraction grating, what should be done?

• A.The slit separation should be decreased
• B.The slit separation should be increased
• C.The wavelength of light should be decreased
• D.The number of slits should be reduced

Objects that give out light of their own are said to be?

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

An image formed by a convex lens is called?

• A.Virtual and inverted
• B.Virtual and erect
• C.Real and erect
• D.Real and inverted

A convex lens of focal length 40 cm is in contact with a concave lens of focal length 25 cm. The power of the combination in diopters is?

• A.+1.5
• B.-1.5
• C.+6.5
• D.-6.5

Why does the colour of the ocean appear blue?

• A.Because the ocean floor reflects blue light
• B.Because water molecules are naturally blue in colour
• C.Because sunlight falling on it is scattered
• D.Because the sky's blue colour is absorbed by water

Past Paper MCQ

The speed of light is ?

• A.500,000 km/s
• B.150,000 km/s
• C.300,000 km/s
• D.3,000 km/s

A narrow beam of white light passes from air into glass and is refracted. Which wave characteristic remains unchanged?

• A.Wavelength
• B.Speed
• C.Frequency
• D.Amplitude

What is the method of following individual rays of light from an object to the eye called?

• A.Optical diffraction
• B.Refraction mapping
• C.Light scattering
• D.Ray tracing

What type of vision problem can be corrected using a concave lens?

• A.Farsightedness
• B.Astigmatism
• C.Nearsightedness
• D.Cataract

A typical diffraction grating has lines per centimeter ?

• A.400-5000
• B.400-50000
• C.40-500
• D.4000-500000