Electronics and Experimental Methods (CSIR (Council of Scientific & Industrial Research) Physical Sciences): Questions 17 - 19 of 50

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Question number: 17

» Electronics and Experimental Methods » Semiconductor Devices » Diodes

Appeared in Year: 2013

MCQ▾

Question

Two identical Zener diodes are placed back to back in series and are connected to a variable DC power supply. The best representation of the I – V characteristics of the circuit is – (December)

Choices

Choice (4) Response

a.

I – V characteristics: Choice A

I – v Characteristics: Choice A

Figure shows I – V characteristic of circuit consists of two identical Zener diodes.

b.

I – V characteristics: Choice B

I – v Characteristics: Choice B

Figure shows I – V characteristic of circuit consists of two identical Zener diodes.

c.

I – V characteristics: Choice C

I – v Characteristics: Choice C

Figure shows I – V characteristic of circuit consists of two identical Zener diodes.

d.

I – V characteristics: Choice D

I – v Characteristics: Choice D

Figure shows I – V characteristic of circuit consists of two identical Zener diodes.

Question number: 18

» Electronics and Experimental Methods » Semiconductor Devices » Junctions

Appeared in Year: 2014

MCQ▾

Question

A junction is made between a metal of work function Equation and a doped semiconductor of work function Equation withEquation . If the electric field at the interface has to be increased by a factor of 3, then the dopant concentration in the semiconductor would have to be – (December)

Choices

Choice (4) Response

a.

Decreased by a factor of Equation

b.

Decreased by a factor of 3

c.

Increased by a factor of 3

d.

Increased by a factor of 9

Question number: 19

» Electronics and Experimental Methods » Opto-Electronic Devices » LEDs

Appeared in Year: 2012

MCQ▾

Question

An LED operates at 1.5 V and 5 mA in forward bias. Assuming an 80 % external efficiency of the LED, how many photons are emitted per second? (June)

Choices

Choice (4) Response

a.

Equation

b.

Equation

c.

Equation

d.

Equation

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