An electron enters the p-n junction from the n-side with a velocity of $5 \times 10^5 m/s$ . If the depletion region is $5 \times 10^{-7} m/s$ wide and the potential barrier is $0.5 V$ What will be its speed When it enters P side ?

Question

$(a)\;1.4 \times 10^5 m/s \\ (b)\;2.7 \times 10^5 m/s \\ (c)\;0.4 \times 10^5 m/s \\ (d)\;1.8 \times 10^5 m/s$