Question

MCQ BASED QUESTION
please help me​

Answer 1

Question

Which of the following is an incorrect representation of angle of incidence and angle of reflection?

Answer

Option 3

Explanation

In the first figure, the light ray is coming from focus and is reflected parallel to the principal axis. Hence the ray diagram is correct. Also, angle of incidence and angle of reflection are measured from the normal. Hence this figure is correct.

In the second, light ray is hitting the pole. Here, the normal and principal axis coincides and angle of incidence or reflection are measured from that, hence the diagram is also correct.

In the third, we have light ray passing through centre of curvature and hitting the concave mirror. Here, since the light ray retraces its original path, the angle of incidence and reflection, both should be zero (because the light itself hits at right angle with respect to the surface). Hence this figure is incorrect.

In the fourth, the light is coming parallel to the principal axis and the reflected ray appears to meet at focus. Also, the normal drawn passes through centre of curvature, hence the figure is correct.

Hence, our answer is figure 3.