The expected answers are:

(a) Any two correct effects that show the existence of matter waves e.g.

-diffraction of electrons
-diffraction pattern by reflecting hydrogen and helium molecules from a crystal surface to walk on the surface of water
-diffraction of neutron from crystal surface

(b)Any two correct effects that show radiation behaves like waves e.g.

-Photoelectric effect
-Compton effect
-Quantization of radiation energy proposed by Plank
-Black body radiation.
-Emission/absorption spectra.

This question on wave particle duality of matter was the least popular in this part. The performance was however fair.
In part (a), some candidates wrongly listed the properties of waves while in part (b) some candidates could not really understand the demand of the question.