Physics - Modern Physics Question with Solution | TestHub

Relation between kinetic energy and momentum is as follows: $P=\frac{1}{\sqrt{2mK}}$ If kinetic energy is tripled, the new momentum is given by, $P^{\prime }=\frac{1}{\sqrt{2m(3K)}}=\frac{P}{\sqrt{3}}$ de-Broglie wavelength of an electron is the following ratio: $\lambda =\frac{h}{P}$ Therefore, on tripling the kinetic energy the wavelength will change to: ${\lambda }^{\prime }=\frac{h}{P^{\prime }}=\sqrt{3}\left(\frac{h}{P}\right)=\sqrt{3}\lambda$