Answer –

According to the question –

 Angle of deflection is θ = 3.5°

The distance of the screen from the mirror is D = 1.5 m

The deflection undergone by the reflected rays are twice the angle of deflection, so –

2θ = 7.0°

The displacement (d) of the reflected spot of light is determined in the following manner –

$\tan 2\Theta =\frac{d}{1.5}$

Therefore, we have –

d = 1.5 x tan7^o = 0.184 m

d = 18.4 cm

Hence, 18.4 cm is the displacement of the refracted spot of light.