Question 5
(a) Explain the wave-particle duality of light.
(b) A particle of wavelength 4.2 x 10-11m travels with a momentum of 1.6 x 10-23 kg ms-1. Determine the value of the Planck’s constant, h.
Observation
This question was attempted by very few candidates whose performance was poor.
The expected answer
(a) Explanation of Wave Particle Duality of Light
Light can act as a particle (by way of Photon) and also as waves (but not simultaneously)(1)
(b) Determination of Planck’s Constant
h = λp
= 4.2 x 10-11 x 1.6 x 10-23
= 6.72 x 10-34Js