Assertion (A): A ray of light which is incident normally (or perpendicularly) on a mirror, is reflected back along the same path. Reason (R): When a ray of light falls perpendicularly, it means that it goes along the ‘normal’ to the mirror surface. The angle of incidence as well as the angle of reflection for such a ray of light are zero, and hence it is reflected back along the same path.

Question

KollegeApply · Accepted Answer

Both A and R are true and R is correct explanation of the assertion. Explanation: Assertion (A) is true because a normally incident ray retraces its path upon reflection off a mirror surface. Reason (R) correctly explains this behaviour using the law of reflection, noting that a perpendicular ray travels directly along the normal. Because the light line merges with the normal line, the angle of incidence drops to zero (i = $0^\circ$), which forces the angle of reflection to equal zero (r = $0^\circ$) and causes the exact path reversal.

AChoose Your Answer