SOLUTION

When the external voltage applied to the P-N junction is in such a direction that the depletion (potential) barrier is increased, it is called reverse bias.

When the reverse voltage increases from 5V to 10V, the depletion layer increased.

The negative terminal of the battery is connected to P-type and the positive terminal to N-type. The reverse biasing establishes an electric field that acts in the same direction as the field due to the depletion (potential) barrier. Thus, the depletion (potential) barrier is increased and prevents the flow of charge carriers across the junction. In effect, a high resistance path is established for the circuit, hence, the current flow is insignificant. By increasing the reverse voltage the width of the depletion layer is increased upto a certain point.

If the reverse-biased voltage exceeds a certain level (usually 50 V or more), the diode “breaks down” and the reverse current starts flowing from cathode to anode. The reverse voltage at which the diode breaks down is known as the peak reverse voltage (PRV), or peak inverse voltage (PIV).