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# Test: The Continuity Equation

## 10 Questions MCQ Test Electronic Devices | Test: The Continuity Equation

Description
This mock test of Test: The Continuity Equation for Electrical Engineering (EE) helps you for every Electrical Engineering (EE) entrance exam. This contains 10 Multiple Choice Questions for Electrical Engineering (EE) Test: The Continuity Equation (mcq) to study with solutions a complete question bank. The solved questions answers in this Test: The Continuity Equation quiz give you a good mix of easy questions and tough questions. Electrical Engineering (EE) students definitely take this Test: The Continuity Equation exercise for a better result in the exam. You can find other Test: The Continuity Equation extra questions, long questions & short questions for Electrical Engineering (EE) on EduRev as well by searching above.
QUESTION: 1

### What does p/τ represent?

Solution:

Option (c) represents the holes per second lost by recombination per unit volume.

QUESTION: 2

### Which of the following is the Taylor’s expression?

Solution:

Option a represents the correct formula for the Taylor’s expression.

QUESTION: 3

### Calculate the number of coulombs per second if the area is 4cm2, recombination rate of hole is 1000 cm-3/s and the differential length is 2mm.

Solution:

number of coulombs per second= eAdxp/τ
=1.6*10-19*4*10-4*2*10-3*1000
=1.28*10-22.

QUESTION: 4

The current entering the volume at x is I and leaving is I+Δi , the number of coulombs per second will be equal to δI. Is it true or false?

Solution:

Coulombs per second is known as the current. The differential current will be the current through the semiconductor.

QUESTION: 5

The change in the carrier density is due to

Solution:

The change in the carrier density describes the continuity equation which is equal to the difference between the incoming and outgoing flux plus generation and minus recombination.

QUESTION: 6

What of the following conditions satisfies when the number of holes which are thermally generated is equal to the holes lost by recombination?

Solution:

Under the equilibrium conditions, I will be zero and then the dp/dt will aso be equal to zero in the continuity equation. Then, g= p/τ is left which is option c.

QUESTION: 7

What is the diffusion length for holes when Dp=25cm2/s and τp=25s?

Solution:

Lp=√(Dpp)
=√(25*25)
=25cm.

QUESTION: 8

Which of the following represents the continuity equation?

Solution:

Option a represents the correct equation of the continuity equation for holes.

QUESTION: 9

What is the diffusion length for electrons when Dn=10cm2/s and τn=40s?

Solution:

Ln=√(Dnn)
=√(10*40)
=20cm.

QUESTION: 10

Which of the following represents the best definition for the diffusion length for holes?

Solution:

Diffusion length for holes is represented as the average distance which a hole is injected travels before recombining with an electron. It is the distance into the semiconductor at which the injected concentration falls to 1/ϵ of its value at x=0.