NEET2018Physics-Modern Physics

NEET 2018 Physics de-Broglie Wavelength MCQ Question

Type: MCQ-conceptual-Medium-Class 12

An electron of mass m with an initial velocity v=v0i^\vec{v} = v_0 \hat{i} (v0>0v_0 > 0) enters an electric field E=E0i^\vec{E} = -E_0 \hat{i} (E0=constant>0E_0 = \text{constant} > 0) at t=0t = 0. If λ0\lambda_0 is its de-Broglie wavelength at time t is

A

λ0(¹+eE0tmv0)\frac{\lambda_0}{\left(¹⁺ \frac{eE_0 t}{m v_0}\right)}

B

λ0(¹+eE0tmv0)\lambda_0 \left(¹⁺ \frac{eE_0 t}{m v_0}\right)

C

λ0\lambda_0

D

λ0t\lambda_0 t

Correct Answer

Option B

Detailed Explanation

The de-Broglie wavelength λ\lambda is given by λ=hmv\lambda = \frac{h}{mv}. As the electron enters the electric field, its velocity changes due to the force exerted by the field, leading to a change in its wavelength.

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