JEE Main & Advanced Physics Current Electricity, Charging & Discharging Of Capacitors / वर्तमान बिजली, चार्ज और कैपेसिटर का निर JEE PYQ-Current Electricity Charging and Discharging of Capacitors

de-Broglie wavelength of an electron accelerated by a voltage of 50 V is close to [JEE ONLINE 10-04-2015] \[(|e|=1.6\times {{10}^{-19}}C,{{m}_{e}}=9.1\times {{10}^{-31}}kg,h=6.6\times {{10}^{-34}}Js)\]

A) \[0.5{\AA}\]

B) \[1.7{\AA}\]

C) \[2.4{\AA}\]

D) \[1.2{\AA}\]

Correct Answer: B

Solution :

[b]

momentum \[P=\sqrt{2mE}\] and \[E=eV\]

\[\lambda =\frac{h}{p}=\frac{h}{\sqrt{2mE}}\]

\[=\frac{6.6\times {{10}^{-34}}}{\sqrt{2\times 9.1\times {{10}^{-31}}\times 1.6\times {{10}^{-19}}\times 50}}\]

\[=1.7\times {{10}^{-10}}M\]

\[=1.7{\AA}\]