CBSE Class 10 Answered

This can happen if the colour of the glass slab is red. The light rays incident on the front surface of the slab are partially reflected carrying all the colors emitted by the bulb producing an image that is white in color. The other part of the incident rays enter the glass slab and are reflected by the second surface producing the second image. As these rays travel through the glass the colors other than red are striped off and the produced image appears to be red.