Physics - Modern Physics Question with Solution | TestHub

de-Broglie wavelength of an electron $$\begin{array}{l}\lambda =\frac{\mathrm{h}}{\mathrm{mv}}=\frac{\mathrm{h}}{\sqrt{2\mathrm{mK}}}\text{ or }\lambda \propto \frac{1}{\sqrt{\mathrm{K}}}\\ \therefore \frac{{\lambda }^{\prime }}{\lambda }=\frac{1}{\sqrt{3\mathrm{K}}}=\frac{\sqrt{\mathrm{K}}}{1}=\frac{1}{\sqrt{3}}\end{array}$$ or ${\lambda }^{\prime }=\frac{\lambda }{\sqrt{3}}$ i.e. de-Broglie wavelength will change by factor $\frac{1}{\sqrt{3}}$.