On Diwali night, a polished steel thali beside the diyas gleams brightly
On Diwali night, a polished steel thali beside the diyas gleams brightly. Shubham says the thali is a source of light too, just like the diyas, because it is shining. Noor says the thali is not a source of light at all. Who has it right?
Who do you think is right? Pick one.
The answer: Noor is right, the thali reflects the diyas' light and makes none of its own
Why
Shubham is correct that the thali is sending light to his eyes — that is why he can see it gleam. But sending light and making light are different things. A diya's flame produces its own light: it is luminous, a source of light. The steel thali produces none; it only bounces back the light that falls on it from the diyas, and because it is smooth and shiny it reflects that light strongly, so it gleams. Objects like this are non-luminous — we see them only because they reflect light that comes from a source. Test: carry the thali into a completely dark room with no diya in it — the thali disappears into the dark, while a diya lit in the same room keeps glowing on its own. Noor is right: the thali is not a source of light; it only reflects the light of the diyas.
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