The figure shows the path of a ray of light as it travels through air and crosses a boundary into water.The index of refraction of water for this light is 1.33.

-What is the speed of this ray of light as it travels through the water?
A)1.54 × 10⁸ m/s
B)2.26 × 10⁸ m/s
C)2.86 × 10⁸ m/s
D)3.99 × 10⁸ m/s
E)4.43 × 10⁹ m/s

Question

The figure shows the path of a ray of light as it travels through air and crosses a boundary into water.The index of refraction of water for this light is 1.33.
 
-What is the speed of this ray of light as it travels through the water?
A)1.54 × 10⁸ m/s 
B)2.26 × 10⁸ m/s 
C)2.86 × 10⁸ m/s 
D)3.99 × 10⁸ m/s 
E)4.43 × 10⁹ m/s

Quizplus · Accepted Answer

The speed of light in a vacuum is approximately 3.0 × 10⁸ m/s. The speed of light in a medium is given by v = c/n, where c is the speed of light in a vacuum and n is the refractive index of the medium. In this case, the refractive index of water is 1.33. Therefore, the speed of light in water is:
v = c/n = (3.0 × 10⁸ m/s) / 1.33 = 2.26 × 10⁸ m/s. Thus, the best choice is (B).

The Figure Shows the Path of a Ray of Light