Practice free Semiconductor Electronics: Materials, Devices and Simple Circuits (Physics) NEET multiple-choice questions online with instant answers and detailed explanations. No login required.
The approximate ratio of resistances in the forward and reverse bias of the PN-junction diode is
(d) Resistance in forward biasing and resistance in reverse biasing
In a junction diode, the holes are due to
(d) The holes are created due to missing electrons.
In forward bias, the width of potential barrier in a P-N junction diode
(b) In forward biasing width of depletion layer decreases.
The cause of the potential barrier in a P-N diode is
During the formation of a junction diode, holes from p- region diffuse into n-region, and electrons from n-region diffuse into p-region. In both cases, when an electron meets a hole, they cancel the effect at each other and as a result, a thin layer at the junction becomes free from any of charges carriers. This is called the depletion layer. There is a potential gradient in the depletion layer, negative on the p-side, and positive on the n-side. The potential difference thus developed across the junction is called the potential barrier.
In a PN-junction diode not connected to any circuit
Which of the following statements is not true
(c) In N-type semiconductor majority charge carriers are electrons.
The dominant mechanisms for motion of charge carriers in forward and reverse biased silicon P-N junctions are
(b) In forward biasing the diffusion current increases and drift current remains constant so net current is due to the diffusion.
In reverse biasing diffusion becomes more difficult so net current (very small) is due to the drift.
The reason of current flow in P-N junction in forward bias is
(c) In forward biasing of PN-junction diode, current mainly flows due to the diffusion of majority charge carriers
The resistance of a reverse biased P-N junction diode is about
(d) The resistance of a reverse biased P-N juction is about 106 ohm
Avalanche breakdown is due to
(a) At high reverse voltage, the minority charge carriers, acquires very high velocities. These by collision break down the covalent bonds, generating more carriers. This mechanism is called Avalanche breakdown.
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