Wavefront and Huygens' principle — NEET & JEE Questions

Question 1 · difficulty L1 · recall

A wavefront is a surface joining points that have

• A. the same amplitude only regardless of phase
• B. zero frequency
• C. the same phase
• D. the same velocity direction only

Question 2 · difficulty L1 · understanding

According to Huygens' principle, every point on a wavefront acts as

• A. a perfect absorber
• B. a magnetic monopole
• C. a stationary mirror only
• D. a source of secondary wavelets

Question 3 · difficulty L2 · understanding

For a point source in a homogeneous isotropic medium, wavefronts are

• A. spherical
• B. always plane
• C. cylindrical only
• D. random surfaces

Question 4 · difficulty L2 · application

For a plane wave propagating in a uniform medium, rays are

• A. tangent to wavefronts
• B. normal to the plane wavefronts
• C. parallel to E only and not propagation
• D. randomly directed

Question 5 · difficulty L2 · understanding

A wavefront is a surface joining points of a wave that are

• A. in the same phase
• B. at different frequencies only
• C. at rest
• D. moving in opposite media only

Question 6 · difficulty L3 · application

Huygens' principle can reproduce the law of reflection by comparing

• A. only photon momentum with no wave construction
• B. charges on the mirror
• C. the envelope of secondary wavelets at the reflecting surface
• D. thermal emission from the mirror

Question 7 · difficulty L3 · application

Huygens' construction of refraction reflects the fact that wave speed

• A. is identical in all media
• B. becomes infinite at an interface
• C. depends only on amplitude
• D. changes across media with different refractive indices

Question 8 · difficulty L3 · application

According to Huygens' principle, every point on a wavefront acts as

• A. a source of secondary wavelets
• B. a permanent absorber of the wave
• C. a mirror only
• D. a point with zero disturbance

Question 9 · difficulty L3 · application

Far from a small point source in a uniform medium, a small portion of a spherical wavefront can be approximated as

• A. a plane wavefront
• B. a cylindrical wavefront only
• C. no wavefront
• D. a standing-wave node

Question 10 · difficulty L4 · analysis

A plane wavefront enters a slower medium obliquely. The refracted wavefront orientation changes so the ray bends

• A. toward the normal
• B. away from the normal
• C. along the interface always
• D. back into the first medium only