Description

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

QUESTION: 1

What is the SI unit of electron diffusion constant?

Solution:

J=eDdn/dx

So D=q*m/ (q*s*(1/m))

=m^{2}/s.

QUESTION: 2

Calculate the diffusion current density when the concentration of electron varies from the 1*10^{18} to 7*10^{17} cm^{-3} over a distance of 0.10 cm.D=225cm^{2}/s

Solution:

J=eDdn/dx

J=1.6*10^{-19}*225*(10^{18}-(7*10^{17}))/0.1

=108A/cm^{2}.

QUESTION: 3

Which is the correct formula for the Jp?

Solution:

Jp is negative for the p type of semiconductors.

QUESTION: 4

What is the direction of the electron diffusion current density relative to the electron flux?

Solution:

From the graph between electron concentration and the distance, we can see that the direction of the electron diffusion current density is opposite to the electron flux.

QUESTION: 5

In diffusion, the particles flow from a region of _______ to region of ___________

Solution:

Diffusion is the process of flow of particles form the region of the high concentration to a region of low concentration.

QUESTION: 6

Which of the following parameter describes the best movement of the electrons inside a semiconductor?

Solution:

Mobility is defined as the movement of the electrons inside a semiconductor. On the other hand, velocity gradient is the ratio of velocity to distance.

QUESTION: 7

Which of the following term isn’t a part of the total current density in a semiconductor?

Solution:

J=enµE+epµE+eDdn/dx-eDdp/dx

So, temperature isn’t a part of the equation.

QUESTION: 8

What does dn/dx represent?

Solution:

QUESTION: 9

Calculate the diffusion constant for the holes when the mobility of the holes is 400cm^{2}/V-s and temperature is 300K?

Solution:

: D_{p}=V_{T}*μn

= (1.38*10^{-23}*300*400*10^{-2})/ (1.6*10^{-19})

= 1.035m m^{2}/s.

QUESTION: 10

Calculate the diffusion constant for the electrons when the mobility of the electrons is 325cm^{2}/V-s and temperature is 300K?

Solution:

D_{n}=V_{T}*μn

= (1.38*10^{-23}*300*325*10^{-2})/ (1.6*10^{-19})

= 0.084 m^{2}/s.

### Diffusion Process

Doc | 4 Pages

### Multicomponent Diffusion

Doc | 1 Page

### Steady State Diffusion

Video | 04:48 min

### Means of Transport-Diffusion

Video | 06:38 min

- Test: Diffusion
Test | 10 questions | 10 min

- Test: Multicomponent Diffusion
Test | 5 questions | 10 min

- Test: Diffusion Of Gases
Test | 22 questions | 22 min

- Test: Molecular Diffusion In Solids
Test | 10 questions | 20 min

- Test: Molecular Diffusion In Liquids
Test | 10 questions | 20 min