Question

If kinetic energy of a proton is increased nine times the wavelength of the de-Broglie wave associated with it would become

• A. 3 times
• B. 9 times
• C. $\frac{1}{3}$ times
• D. $\frac{1}{9}$ times.

Answer 1

Answer: (C)

$\frac{1}{3}$ times

Answer 2

l = $\frac{h}{\sqrt{2mE}}$

$\frac{\lambda_{1}}{\lambda_{2}}$ = $\sqrt{\frac{E_{2}}{E_{1}}}$ = $\sqrt{\frac{9E_{1}}{E_{1}}}$ = 3

l₂ = $\frac{1}{3}$l₁.