In Huygens principle, the relation between wavefront and the ray of light is-

The correct answer is option 1) i.e. Ray of light is perpendicular to the wavefront.

CONCEPT:

• Huygens principle: It states that each point on a wavefront is a source of wavelets, which spread forward with the same speed.
• Wavefront: A wavefront is a surface or a line on which the disturbance at every point has the same phase.
• Wavelets: It is a wave-like oscillation with an amplitude that starts at zero, increases, and then decreases back to zero.

EXPLANATION:

• A wavefront is a locus of all the points in a wave that have the same phase.
• The wavefront forms consecutive concentric circles around the source of light.
• The rays show the direction of propagation of the wave.
• Therefore, the rays of light are always normal/perpendicular to the wavefront.