. A poster coloured with green, yellow and red pigments is observed through a pure red glass. How do the following appear to the observer: (a) the green part (b) the yellow part and (c) the red part of the poster?
(a)The green part appears black when viewed through a red glass. (b)The yellow part appears black when viewed through a red glass. (c)The red part appears red since a red glass allows only red colour (wavelength) to pass through it and absorbs all other colours (wavelengths) of the white light.