Question

In the below image, for Rahul, what is/are the luminous object(s) among the torch, the mirror, and the screen?

Answer 1

Luminous objects are those that can produce their own light.
The torch is producing its own light using the energy from the battery inside it. Hence, it is a luminous object.
The mirror is getting illuminated by the light coming from the torch. The mirror is just reflecting the incoming light at the screen. It is not producing any light of its own. Hence, it is a non-luminous object.
The screen appears to be glowing. However, the glow is due to the light falling on it after reflection from the mirror. Thus, the screen is also a non-luminous object