• # question_answer The de-Broglie wavelength of an electron having $80eV$ of energy is nearly             ($1\,eV=\text{ }1.6\times {{10}^{19}}J,$  Mass of electron $=9\times {{10}^{-31}}kg$ Planks constant $=6.6\times {{10}^{-34}}J\text{-}\,\sec$) A) 140 $\overset{\text{o}}{\mathop{\text{A}}}\,$ B) 0.14 $\overset{\text{o}}{\mathop{\text{A}}}\,$ C) 14 $\overset{\text{o}}{\mathop{\text{A}}}\,$ D) 1.4 $\overset{\text{o}}{\mathop{\text{A}}}\,$

[b] If an electron and a photon propagates in the from of waves having the same wavelength, it implies that they have same momentum. This is according to de-Broglie equation, $p\propto \frac{1}{\lambda }$