186. Primary colours are
(a) colours of the rainbow
(b) colours in the spectrum of white light
(c) colours which cannot be produced by mixing other colours
(d) colours found in nature
187. In the visible spectrum which colour has the shortest wavelength?
188. When white light passes through a glass prism we get a spectrum on the
other side of the prism. In the emergent beam the ray which is deviated least
(a) the violet ray
(b) the red ray
(c) the green ray
(d) the blue ray
189. Which part of the eye photographic camera?
190. The red colour of the setting sun is due to