The reflecting surfaces of two intersecting flat mirrors are at an angle of 60 , as shown in the figure.

The reflecting surfaces of two intersecting flat mirrorsareatanangle of 60 ◦ , as shown in the figure. A light ray strikes the horizon- tal mirror, reflects off the horizontal mirror, impinges on the raised mirror, reflects off the raised mirror, and proceeds in the right-hand direction.Calculate the angle φ. Answer in units of ◦.