A long horizontal slit is placed above a horizontal plane mirror

PHYSICS · Single correct · A Level · Physics · Waves · Waves

Problem

A long horizontal slit is placed

1\,\text{mm}

above a horizontal plane mirror. Interference between light coming directly from the slit and light reflected from the mirror is seen on a screen

1\,\text{m}

away from the slit. If the mirror reflects only

64\%

of the incident light, the ratio of maximum to minimum intensity in the interference pattern is (1)

8:1

(2)

3:1

(3)

81:1

(4)

9:1