An electron with mass ' m ' with an initial velocity (t=0) v =v_0 i (v_0 0) enters a magnetic field B =B_0 j . If the initial de-Broglie wavelength at t=0 is λ_0 then its value after time ' t ' would be :

Correct answer: D. λ_0 Magnetic field does not work Speed will not charge, so De-Broglie wavelength remains same.

JEE Main 20252 AprilEvening Shift

JEE Main 2025 · 2 April · Evening Shift · Physics · Dual Nature of Matter

An electron with mass ' m ' with an initial velocity (t=0) v =v_0 i...

An electron with mass '

m

' with an initial velocity

(\mathrm{t}=0) \overrightarrow{\mathrm{v}}=\mathrm{v}_0 \hat{\mathrm{i}} \quad

\left(\mathrm{v}_0 \gt 0\right)

enters a magnetic field

\vec{B}=B_0 \hat{j}

. If the initial de-Broglie wavelength at

\mathrm{t}=0

is

\lambda_0 then its value after time ' t ' would be :

A $\frac{\lambda_0}{\sqrt{1-\frac{\mathrm{e}^2 \mathrm{~B}_0^2 \mathrm{t}^2}{\mathrm{~m}^2}}}$
B $\frac{\lambda_0}{\sqrt{1+\frac{\mathrm{e}^2 \mathrm{~B}_0^2 \mathrm{t}^2}{\mathrm{~m}^2}}}$
C $\lambda_0 \sqrt{1+\frac{\mathrm{e}^2 \mathrm{~B}_0^2 \mathrm{t}^2}{\mathrm{~m}^2}}$
D $\lambda_0$

D. $\lambda_0$

Magnetic field does not work

\therefore

Speed will not charge, so De-Broglie wavelength remains same.