Practice portal › Dual Nature of Matter and Radiation › Photons, Matter Waves and X-rays

The de Broglie wavelength associated with a particle of rest mass m₀ moving with the speed of light in vacuum is ______.

Asked in GSEB Board July 2017 · de Broglie relation and its graphs

Answer: (2) 0

Step-by-step solution

Given: rest mass m₀, speed v = c.

Idea: λ = h/p = h/(mv), where the mass of the moving particle is m = (m₀)/(√1 - v²/c²).

As v → c, √1 - v²/c² → 0, so m → ∞ and p = mv → ∞.

Then λ = h/p → 0.

(A particle with rest mass can never actually reach c; the answer describes the limit.)

So the de Broglie wavelength is 0.

Why the other options are wrong

More Photons, Matter Waves and X-rays questionsAll Photons, Matter Waves and X-rays questions →

Reading this solution needs no sign-in. You only sign in to practise against the clock and keep your progress.

Practise this with a timer