(i) In which circuit will the lamp glow when switched on?

(ii) What is the function of a diode?

(i). The first case where p-side of the diode is connected to the positive terminal of the battery and n-side to the negative terminal of the body is the circuit in which the lamp glow when switched on. While in the second the exact opposite happens the p-side is connected to the negative terminal ad n-side connected to the positive terminal and the lamp will not glow. This happens so because when we connect p-side of the diode to the positive terminal of the body the diode behaves as a conductor and allows the current to flow and this is called forward biasing but when it is connected in opposite direction the diode will behave as a resistor and this is called reverse bias.

(ii). The diode is a semiconductor device which is consisted of two parts formed by suitable doping of two different type of semiconductor material i.e. p-side and n-side.

Ø P-side is the region of the diode which have plenty of holes or we say plenty of positive charge carrier and n-side is the region of the diode which have plenty of electrons or we say negative charge carrier.

Ø When n-region is connected to the negative terminal and p-side to the positive terminal, the electrons from the negative terminal force the electrons of n-region to move forward and allow the flow of current and this is called forward biasing. While the exact opposite happens in reverse biasing.

Ø Now as mentioned, the diode can act as a conductor as well as a resistor or it can also allow a certain number of electrons to flow. This is the main function of the diode; to control the flow of the electrons, in various electronic device.