The Fig. 10.22 shows three different situations where a light ray falls on a mirror: Class 8

The Fig. 10.22 shows three different situations where a light ray falls on a mirror: Class 8

The Fig. 10.22 shows three different situations where a light ray falls on a mirror: Class 8

(i) The light ray falls along the normal.

(ii) The mirror is tilted, but the light ray still falls along the normal to the tilted surface.

(iii) The mirror is tilted, and the light ray falls at an angle of 20° from the normal.

Draw the reflected ray in each case (Use a ruler and protractor for accurate drawing). What is the angle of reflection in each case?

Answer:

(i) Light ray falls along the normal

Angle of incidence = 0°

Angle of reflection = 0°

The ray reflects straight back along the same line.

(ii) The mirror is tilted, but the light ray still falls along the normal to the tilted surface

Even though the mirror is tilted, the ray is still perpendicular to the surface.

Angle of incidence = 0°

Angle of reflection = 0°

The ray again reflects straight back along its path.

(iii) The mirror is tilted, and the light ray falls at 20° from the normal

Angle of incidence =20°

By the law of reflection:

Angle of reflection =20°

The reflected ray will make a 20° angle with the normal, on the opposite side.