Question

If the kinetic energy of an electron is increased 4 times, the wavelength of the de Broglie wave associated with it would become

• A. 4 times
• B. 2 times
• C. 0.5 times
• D. 0.25 times

Answer 1

The correct option is C 0.5 times

$\lambda =\frac{h}{\sqrt{2.m.K_E}}$
$\frac{{\lambda }_1}{{\lambda }_2}=\sqrt{\frac{K_{E_2}}{K_{E_1}}}$
$\frac{{\lambda }_1}{{\lambda }_2}=\sqrt{\frac{4}{1}}$
${\lambda }_2=\frac{{\lambda }_1}{2}$