Two plane mirrors are inclined to each other at some angle. A ray of light incident at an angle of 30° on one of the mirrors, after reflection from the other, retraces its path. The angle (in degree) between the mirrors

Question

Two plane mirrors are inclined to each other at some angle. A ray of light incident at an angle of 30° on one of the mirrors, after reflection from the other, retraces its path. The angle (in degree) between the mirrors (A)  (B)  (C)  (D)

Tardigrade Admin · Accepted Answer

<img class="img-fluid question-image" alt="Solution" src="https://cdn.tardigrade.in/q/nta/p-qwoj11lni32mso3n.jpg" /> angle i=∠r=30° ∴ angle OIQ=60° ∴ angle IOQ =90° -60° =30°

Q. Two plane mirrors are inclined to each other at some angle. A ray of light incident at an angle of $3 0^{\circ}$ on one of the mirrors, after reflection from the other, retraces its path. The angle (in degree) between the mirrors

$∠ i = ∠ r = 3 0^{\circ}$
$∴ ∠ O I Q = 6 0^{\circ}$
$∴ ∠ I OQ$ $= 9 0^{\circ} - 6 0^{\circ} = 3 0^{\circ}$

Q. Two plane mirrors are inclined to each other at some angle. A ray of light incident at an angle of 30∘ on one of the mirrors, after reflection from the other, retraces its path. The angle (in degree) between the mirrors

∠i=∠r=30∘ ∴∠OIQ=60∘ ∴∠IOQ =90∘−60∘=30∘

Q. Two plane mirrors are inclined to each other at some angle. A ray of light incident at an angle of $3 0^{\circ}$ on one of the mirrors, after reflection from the other, retraces its path. The angle (in degree) between the mirrors

$∠ i = ∠ r = 3 0^{\circ}$
$∴ ∠ O I Q = 6 0^{\circ}$
$∴ ∠ I OQ$ $= 9 0^{\circ} - 6 0^{\circ} = 3 0^{\circ}$