Question

If the kinetic energy of an electron is increased four times, the wavelength of the de-Broglie wave associated with it would become:

• A. Two times
• B. Half
• C. One fourth
• D. Four times

Answer 1

The correct option is B Half

Kinetic energy of a particle $E=\frac{1}{2}m{v}^2$

If $E$ is increased by 4 times, new velocity is double the old velocity$=2v$

debroglie wavelength $\lambda =\frac{h}{mv}$

if velocity is doubled, $\lambda$ is halved.