Physics 2004 JAMB Past Questions - Question 6: What happens to the rays in a parallel beam of light?

Correct Answer

D

Explanation

In a parallel beam of light, the rays travel in a straight line and maintain their relative positions. This is because the light rays are all traveling in the same direction and are not being refracted (bent) or dispersed as they pass through a uniform medium, such as air or a vacuum.

When a parallel beam of light encounters a different medium, such as passing from air into glass or water, the light rays may undergo refraction. Refraction is the bending of light as it passes from one medium to another with a different refractive index. The amount of bending depends on the refractive indices of the two media and the angle at which the light enters the second medium, as described by Snell's Law.

So, in summary, in a uniform medium, a parallel beam of light will continue to travel in parallel without any convergence or divergence. However, when it encounters a different medium, the light rays may bend, but they will still maintain their relative positions within the beam.