Why is a red light used in traffic signals?

A. It has the longest wavelength

B. It has the highest frequency

Electromagnetic waves travel with _?

D. Variable speed depending on frequency

Everyday Science · Physics in Everyday Life · page 17 of 44

Light & Optics MCQs with Answers

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Light & Optics (incl. Lenses) MCQs (161–170)

10 MCQs with answers and a short one-liner. Hide answers to test yourself.

Past paper MCQs in this chapter · See all past papers

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161.
Why is a red light used in traffic signals?
Correct Answer: A. It has the longest wavelength
One-liner
Red light is used in traffic signals because it has the longest wavelength in the visible spectrum, allowing it to scatter the least and be seen from the greatest distance.
162.
What occurs when light bounces off a shiny surface?
Correct Answer: B. Reflection
One-liner
The bouncing back of light from a shiny surface is called reflection.
163.
Light passes through two parallel slits and falls on a screen. The pattern produced is due to interference and ?
Correct Answer: D. Diffraction
One-liner
The pattern produced in Young's double-slit experiment is due to both interference and diffraction of light.
164.
Transverse nature of light was confirmed by the phenomenon of ?
Correct Answer: A. Polarization of light
One-liner
The transverse nature of light was confirmed by the phenomenon of polarization of light.
165.
Electromagnetic waves travel with _?
Correct Answer: C. Speed of light
One-liner
Electromagnetic waves travel with the speed of light in a vacuum, which is approximately 3 × 10⁸ m/s.
166.
When parallel rays of light fall onto a rough surface, they are reflected in different directions and are scattered. This is called _?
Correct Answer: B. Diffused Reflection
One-liner
When parallel light rays strike a rough surface and scatter in different directions, the phenomenon is called Diffused Reflection.
167.
The center of Newton's is dark due to destructive interference.
Correct Answer: C. Rings
One-liner
The center of Newton's Rings is dark due to destructive interference.
168.
Past Paper MCQ
When white light is passed through a prism, it splits into colors.
Correct Answer: C. 7
One-liner
When white light is passed through a prism, it splits into 7 colors (VIBGYOR — Violet, Indigo, Blue, Green, Yellow, Orange, Red).
169.
How many colours are there in the spectrum?
Correct Answer: C. Seven
One-liner
There are seven colours in the spectrum (VIBGYOR): Violet, Indigo, Blue, Green, Yellow, Orange, and Red.
170.
Which device is required to view three-dimensional pictures?
Correct Answer: C. Epidiascope
One-liner
An Epidiascope is a device used to project and view opaque objects, including three-dimensional pictures, onto a screen.

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Light & Optics MCQs with Answers

Light & Optics (incl. Lenses) MCQs (161–170)

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