Elon is standing at the bottom of a well-lit hill while Xara is at the top. Elon holds a flashlight pointing upwards towards Xara. If Xara holds a mirror angled correctly toward Elon, can Elon see the reflection of himself in the mirror and why? Provide a short response.
Yes, Elon can see the reflection of himself in the mirror provided Xara holds it at the correct angle. The flashlight emits a beam of light that travels in a straight line from Elon towards Xara's mirror. When the light from Elon's flashlight hits the mirror, the angle of incidence is equal to the angle of reflection. So if Xara angles the mirror in such a way that the angle of the reflected light beam is directed back down the hill, the beam of light will travel back to Elon's position. Since a mirror reflects most of the light that strikes its surface, and assuming that the hill is sufficiently lit for Elon's eyes to adapt to seeing the bright spot in the mirror, Elon would see the light, and since light carries visual information, he would also see his reflection. However, this is contingent on the angle at which Xara holds the mirror being precise enough to reflect the light directly back to Elon's eyes, which would require both the correct orientation of the mirror's surface and the mirror being held steady during this interaction.