An electron is moving with initial velocity v = V₀j in a magnetic field B = B₀i. Its de-Broglie wavelength will (a) decrease with time. (b) increase and decrease periodically. (c) remains constant. (d) increase with time.

Answer: (c). Magnetic force is always perpendicular to velocity, so it does no work. Speed, hence momentum magnitude p = mv, is constant. λ = h/(mv) is constant. So the answer is (c) remains constant.

An electron is moving with initial velocity v = V₀j in a magnetic… | MHT CET 2026 (20 Apr, Shift 2)

Q23MHT CET 2026 · 20 APR · SHIFT 2Medium

Matter Waves: de Broglie Wavelength

An electron is moving with initial velocity $\vec{v} = V_0\hat{j}$ in a magnetic field $\vec{B} = B_0\hat{i}$ . Its de-Broglie wavelength will

Show answer and solution

Answer: (c)

Magnetic force is always perpendicular to velocity, so it does no work.
Speed, hence momentum magnitude $p = mv$ , is constant.
$\lambda = h/(mv)$ is constant.
So the answer is (c) remains constant.

Report a mistake

Matter Waves: de Broglie Wavelength question from MHT CET 2026 (20 Apr, Shift 2)

More questions on Matter Waves: de Broglie Wavelength