Question

If the de-Broglie wavelength for a proton and for a a-particle are equal, then the ratio of their velocities will be –

• A. 4 : 1
• B. 2 : 1
• C. 1 : 2
• D. 1 : 4

Answer 1

Answer: (A)

4 : 1

Answer 2

l = $\frac{h}{mv}$ ̃ l_p = l_a v µ $\frac{1}{m}$ ̃ $\frac{v_{p}}{v_{\alpha}} = \frac{m_{\alpha}}{m_{p}} = \frac{4m_{p}}{m_{p}} = 4:1$