Light: Mirrors and Lenses

In a clean room a torch makes a circle on the wall, but the beam itself is not visible in between. The same torch in a dusty room shows the whole beam as a bright line. Gopal says the torch becomes stronger in the dusty room. Zoya says the torch is the same and something else explains it. Who is right?

Standing before a mirror, Sameer raises his right hand and the reflection appears to raise its left. He says a mirror swaps left and right. Aarti asks: if that were so, why does it not swap head and feet as well? Is Sameer right?

The power is out and the room is completely dark. Meera says wait a few minutes and their eyes will adjust and the room will become visible. Kabir says with no light at all they will never see it, however long they wait. Who is right?

Deepak uses a magnifying lens to enlarge newspaper print. Then he points the same lens at his sister standing far away, and she appears small and upside down. Deepak says the lens has gone bad. Farah says the lens is fine and only the distance has changed. Who is right?

Anil says only shiny things, a mirror or still water, reflect light; a rough plaster wall does not. Suneeta says you can see the wall, so it must be sending light to your eyes too. Who is right?

A photo Kiran took has come out blurred. She says the phone lens has gone bad. Mohan says that cannot be decided from this alone. Who is right?