Two plane mirrors and meet at an angle

PHYSICS · Single correct · AP · Physics 2: Algebra-based · Geometric Optics · Geometric Optics

Problem

Two plane mirrors

M_1

and

M_2

meet at an angle

\theta

. A light ray strikes

M_1

at an angle of

35^{\circ}

to its normal, reflects to

M_2

, and finally emerges making an angle of

145^{\circ}

with its original direction. Calculate the angle

\theta

between the two mirrors. (a)

75^{\circ}

(b)

52.5^{\circ}

(c)

72.5^{\circ}

(d)

37.5^{\circ}