A beam of light in air is incident on the surface of a rectangular block of clear plastic (n = 1.64).If the velocity of the beam before it enters the plastic is 3.00 × 10⁸ m/s,what is its velocity inside the block? A) 3.00 × 10⁸ m/s B) 1.12 × 10⁸ m/s C) 1.83 × 10⁸ m/s D) 2.34 × 10⁸ m/s E) 1.08 × 10⁸ m/s

Question

Quizplus · Accepted Answer

The velocity of light in a medium is given by v = c/n, where c is the velocity of light in vacuum and n is the refractive index of the medium. Thus, the velocity of the light beam inside the plastic block is v = (3.00 × 10^8 m/s)/(1.64) = 1.83 × 10^8 m/s. Therefore, the best choice is C.

A Beam of Light in Air Is Incident on the Surface