Question

When a semiconductor device is connected in series with a battery and a resistance, a current is found to flow in the circuit. If, however, the polarity of the battery is reversed, practically no current flows in the circuit. The device may be:

• A. A p-type semiconductor
• B. A n-type semiconductor
• C. An intrinsic semiconductor
• D. A p-n junction

Answer 1

The correct option is D A p-n junction

A p-n junction diode has extremely high resistance in one direction (reverse-bias) and extremely low resistance (forward-bias) in the opposite direction. This happens because the depletion layer opposes the flow of current through the semiconductor in the reverse bias.