Physics - Study Mode

[#1] For which one of the following, ''Diodes" are generally used for?
Correct Answer

(A) Rectification

Explanation

Solution: In electronics, a diode is an electronic device that allows current to flow in one direction only. It is mainly used as a rectifier diode that lets electrical current flow in only one direction and is mainly used for power supply operation. Rectifier diodes are used for changing alternating current into direct current.

[#2] The width of depletion layer of a P-N junction
Correct Answer

(D) Is increased under reverse bias

Explanation

Solution: The total width of the depletion region is a function of applied reverse-bias and impurity concentration. Forward bias decreases the depletion region width whilst reverse bias increases it.

[#3] The impurity atoms with which silicon should be doped to make p-type semiconductors are
Correct Answer

(C) Boron

Explanation

Solution: The impurity atoms with which pure silicon should be doped to make a p-type semiconductors are those of Boron and Aluminium that are trivalent in nature. So, they should be added in pure silicon to make p-type semiconductors.

[#4] Which of the following is used for regulated electric supply ?
Correct Answer

(A) Zener diode

Explanation

Solution: The Zener diode is like a general-purpose signal diode. When based in the forward direction it behaves just like a normal signal diode, but when a reverse voltage is applied to it, the voltage remains constant for a wide range of currents and hence widely used for regulated electric supply. The device was named after Clarence Zener, who discovered this electrical property. Many diodes described as “Zener” diodes rely instead on avalanche breakdown as the mechanism. Common applications include providing a reference voltage for voltage regulators, or to protect other semiconductor devices from momentary voltage pulses. Zener diodes are widely used as voltage references and as shunt regulators to regulate the voltage across small circuits.

[#5] A NOT gate can be implemented by:
Correct Answer

(D) A single transistor

Explanation

Solution: A NOT gate can be implemented by a single transistor.