Question

A particle of mass ${}^{\prime }m{}^{\prime }$ is projected from ground with velocity ${}^{\prime }u{}^{\prime }$ making an angle ${}^{\prime }\theta {}^{\prime }$ with the vertical. The de-Broglie wavelength of the particle at the highest point is

• A. $\infty$
• B. $\frac{h}{musin\theta }$
• C. $\frac{h}{mucos\theta }$
• D. $\frac{h}{mu}$

Answer 1

The correct option is B $\frac{h}{musin\theta }$

The particle of depicted in adjacent figure.
Velocity at highest point $=usin\theta$
So, de-Broglie wave length at that point
${\lambda }_D=\frac{h}{musin\theta }$.