Concepts Of Physics MCQ Edition [Volume 1]PhysicsLight Waves
The wavefronts of light arriving from a distant source of unknown shape are approximately
Options
- Aplane
- Bcylindrical
- Celliptical
- Dspherical
Correct answer
A. plane
Step-by-step solution
When a light wave travels a very large distance from its source, the radius of curvature of the wavefront becomes extremely large. As a result, a small portion of the wavefront incident on an observer or an optical instrument appears to be flat. Thus, the wavefronts of light arriving from a distant source are approximately plane wavefronts, regardless of the initial shape of the source.