Answer:
Ans) True , the electron of cation gets excited to higher energy level by absorbing energy and being unstable at excited state returns to the ground state by emitting energy whose wavelength happens to lie in visible region hence they show colour.
Explanation:
True , Different colours have different wavelength , In VIBGYOR , on going from violet to red the wavelength increases.
False, only those show colour whose emission wavelength of radiation lie in visible region.
True, some metal cations will emit colour that are observable
True, anion also contributes to the colour of salt in flame test. A given metal with different anion may give show different colours.