Assertion (A): de Broglie gave dual nature of the light.

Reason (R): Light can behave as particle but not as wave.

A is true but R is false.

de Broglie explains wave particle duality of light which explains that light can behave as particle as well as wave. The phenomena like interference, diffraction and polarization shows the wave nature of light however, photoelectric effect and Compton effect shows the particle nature of the light.