Question

Exp. flaws of Quantum Model proposed by Planck and de-Broglie's hypothesis.

Answer 1

Planck proposed that light is emitted in the form of small packets of energy called photon. And that the particles that emit black body radiation can have only discrete values of energy corresponding to their quantum numbers. Therefore, energy is quantized.
But Planck could not explain how light could show interference and diffraction that could be only shown by waves.
De Broglie said that not only light shows dual behaviour but all radiation and matter show wave particle duality.
But it fails to predict wavelength for macroscopic objects.