Question

In a reverse-biased \[p - n\] junction diode, the \[p\] -type semiconductor is connected to _________ the terminal of the cell and \[n\] -type to the _________ terminal of the cell.
A) positive, positive
B) negative, negative
C) positive, negative
D) negative, positive

Answer 1

Hint: When a \[p - n\] junction is reversed biased, the negative terminal of the battery attracts the free holes in the \[p\]-type towards itself and the positive terminal of the battery attracts the free electrons in \[n\]-type towards itself because of the more positive impurity ions are created in the depletion layer which makes the layer of positive impurity ions thicker.

Complete solution:
Reverse biased \[p - n\] junction: In the presence of applied voltage, a \[p - n\] junction diode blocks the electric current. This process is called the reverse-biased \[p - n\] junction diode. In reverse biased condition the \[n\]-type and \[p\]-type is connected to the positive and negative battery terminals respectively. During the reverse bias condition, the polarity of the potential barrier is the same as the polarity of the voltage source applied. If the reverse-biased voltage across the \[p - n\] junction is increased the barrier potential developed across the \[p - n\] junction is also increased. Due to minority carriers a tiny current flow from n-type region to \[p\]-type region that is thermally generated electrons in \[p\]-type semiconductor and holes in an \[n\]-type semiconductor.
Option \[(D)\] negative, positive.
In a reverse-biased \[p - n\] junction diode, the p-type semiconductor is connected to the negative terminal of the cell and \[n\]-type to the positive terminal of the cell.

Note: Biasing is the process of DC voltage to help the functioning of the circuit. A reverse bias reinforces the potential barrier and impedes the flow of charge carriers. Zener diodes work in reverse bias.