Chapter 16, Problem 34A

We readily note the bending of light by reflection and refraction, but why are we not aware of the bending of light by gravity?

To determine

To explain: The reason for no awareness of the bending of light due to gravity.

Explanation of Solution

Introduction:

According to equivalence principle, the action of gravity should be attributed to the curvature of space-time.

Calculation:

Consider that a light beam is thrown sideways in the “spaceship at rest position” and also assume that this occurs in the absence of gravity.

Consider two observers, one inside and another outside the spaceship.

Then, the light beam will travel in a “straight line path” with respect to both the observer.

When the stationary spaceship starts accelerating, the floor overtakes the light beam and hits the wall just below from where the light is emitted.

The light beam will be in straight line to the “observer present outside the spaceship”.

The light beam will be a curved line to the “observer present inside the spaceship”. This bending of light occurs due to the effect of gravity.

Conclusion:

Thus, the bending of light occurs by reflection, refraction, and also by gravity.