Question

Which of the following generates a plane wavefront ?

• A. $\alpha-rays$
• B. $\beta-rays$
• C. $\gamma-rays$
• D. None of these

Answer 1

Answer: (D)

None of these

Answer 2

When the point source or linear source of light is at very large distance, a small portion of spherical or cylindrical wavefront appears to be plane, such a wavefront is called a plane wavefront.

In the given options none of sources generates plane wavefront, it can be artificially produced by reflection from a mirror or by refraction through a lens.