Question

The de-Broglie wavelength of a vehicle isλ. Its load is changed such that its velocity and energy both are doubled. Its new wavelength will be

• A. λ
• B. $\frac{\lambda}{2}$
• C. $\frac{\lambda}{4}$
• D. 2λ

Answer 1

Answer: (A)

λ

Answer 2

$\lambda = \frac{h}{mv}$ and $E = \frac{1}{2}mv^{2}$ ⇒ $\lambda = \frac{hv}{2E}$ when v and E both are doubled, λ remains unchanged i.e. λ' = λ.