Question

A stream of electrons from a heated filament was passed between two charged plates kept at a potential difference V esu. If e and m are charge and mass of an electron, respectively, then the value of $\frac{h}{\lambda }$ (where $\lambda$ is the wavelength associated with electron wave) is given by:

• A. 2meV
• B. $\sqrt{meV}$
• C. $\sqrt{2meV}$
• D. meV

Answer 1

The correct option is C $\sqrt{2meV}$

K. E. = eV
$\lambda =\frac{h}{\sqrt{2meV}}$
$\frac{h}{\lambda }=\sqrt{2meV}$