Question

A current is passed through a steel wire, which gets heated to dull red. Then half the wire is immersed in cold water. The portion out of water becomes bright. Why?

Answer 1

because the wire immersed in the water cool downs and goes back normal. But the part out of the water is still quite hot. So there is a difference in the colur which makes the hot side more bright


hope it helps

Answer 2

due to the coldness of water the part immersed in water became dull but the part outside the water was still hot that is why it remained bright