When a red glass is heated in dark room it will seem

When a red glass is heated in dark room it will seem
A. black
B. green
C. yellow
D. red

Answer: Green

When a piece of red glass is heated to high temperature, it glows green. Similarly, when a green glass is heated to high temperature, it glows red.

A red glass heated in a furnace when taken out appears green. When it cooled down it appears red because it absorbs green light strongly. When red glass is heated it emit green light strongly.