Question

A potential barrier of 0.5 V exists across a p–n junction and width of the depletion layer is 0.3 μ m. An electron with a speed 5×10⁵ m/s enters p–side from n–side. The velocity of electron in p–side will be (me = 9.1×10^–31 Kg, e = 1.6×10^–19 C) 

(1) 2.5×10⁵ m/s 

(2) 2.7×10⁵ m/s 

(3) 3.7×10⁵ m/s 

(4) 5×10⁵ m/s

Answer 1

Correct option: (2) 2.7×10⁵ m/s

Explanation: 

In a junction diode; due to depeltion layer p–region is at a lower potential than n–region. The electron enters depletion layer from n–region and emerges and from p–region. The electrode is retarded. Let V₁ and V₂ the speed of electron as it enters n–region and emerges out of p–region. Then