⚛️ Physics · Ray Optics and Optical Instruments · NEET & JEE

Speed of light in vacuum is:

Answer: 3 x 10⁸ m/s.

A 3 x 10⁶ m/s
B 3 x 10⁸ m/s
C 3 x 10¹⁰ m/s
D 3 x 10¹² m/s

Correct answer: B. 3 x 10⁸ m/s

Explanation: Speed of light c = 3 x 10⁸ m/s in vacuum. This is the maximum speed in the universe.

Concave mirror ray diagram with an object drawn as a candle on the principal axis, the focal point F marked, and the parallel ray and focal ray reflecting to form an inverted real image

Concave mirror ray construction: a ray parallel to the axis reflects through F, and a ray through F reflects parallel, locating the inverted real image. Image: Maxmath12, CC0, via Wikimedia Commons.

Concept context

Reflection, refraction, lenses, mirrors, total internal reflection.

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Speed of light in vacuum is:

Concept context

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