Electronic Devices and Communication Systems Test

Result

Electronic Devices and Communication Systems Test - 1

Score
-
out of -
Rank
-
out of -

TIME Taken - -

SHARING IS CARING

If our Website helped you a little, then kindly spread our voice using Social Networks. Spread our word to your readers, friends, teachers, students & all those close ones who deserve to know what you know now.

Weekly Quiz Competition

Question 1
1 / -0

The principle of laser action involves

A
amplification of particular frequency emitted by the system

B
population inversion

C
stimulated emission

D
All of the above

Solution

A laser is a device that emits light through a process of optical amplification based on the stimulated emission of electromagnetic radiation. The term "laser" originated as an acronym for "light amplification by stimulated emission of radiation".
Laser action involves all the given phenomena:
(i) Amplification of particular frequency
(ii) Population inversion
(iii) Stimulated emission
Question 2
1 / -0

A p-type material is electrically

A
positive

B
negative

C
neutral

D
It depends on the concentration of p impurities.

Solution

Whenever an impurity is added, the semiconductor remains electrically neutral because the number of electrons and the number of protons added are the same or we can say the impurity added is an atom and not a positive or negative ion.
Question 3
1 / -0

The energy gap between a valence band and a conduction band of a semiconductor is

A
zero

B
infinite

C
0.7eV to 1.3eV

D
>5eV

Solution

The energy gap between a valence band and a conduction band of a semiconductor is between 0.7 eV to 1.3 eV
Question 4
1 / -0

Choose the false statement.

A
Substances with energy gap of the order of 10 eV are insulators.

B
The conductivity of a semiconductor increases with increase in temperature.

C
In conductors, the valence and conduction bands may overlap.

D
The resistivity of a semiconductor increases with increase in temperature.

Solution

Conductivity of the semiconductors increases with increase in temperature. So, statement 4 is false.
Question 5
1 / -0

Choose the correct statement.

A
When we heat a semiconductor, its resistance increases.

B
When we heat a semiconductor, its resistance decreases.

C
When we cool a semiconductor to 0 K, it becomes a superconductor.

D
Resistance of a semiconductor is independent of temperature.

Solution

Semiconductors are the material whose conductivity lies in between that of the insulators and the conductors. At 0 K, the semiconductors are the insulators. As the temperature increases, the conductivity increases, or we say, the resistivity decreases.
Question 6
1 / -0

Which of the following properties does not characterise a semiconductor?

A
At a very low temperature, it behaves like an insulator.

B
At high temperatures, two types of charge carriers will cause conductivity.

C
The charge carriers are all electrons and holes in the valence band at higher temperatures.

D
It is electrically neutral.

Solution

Some of the electrons from the valence band may gain external energy to cross the gap between the conduction band and the valence band. Then, these electrons will move into the conduction band. At the same time, they will create vacant energy levels in the valence band where other valence electrons can move. Thus, the process creates the possibility of conduction due to electrons in the conduction band as well as due to vacancies in the valence band.
Question 7
1 / -0

Carbon, silicon and germanium atoms have four valence electrons each. Their valence and conduction bands are separated by energy band gaps represented by (E_g)_C, (E_g)_Si and (E_g)_Ge, respectively. Which of the following relationships is true in their case?

A
(E_g)_C > (E_g)_Si

B
(E_g)_C = (E_g)_Si

C
(E_g)_C < (E_g)_Ge

D
(E_g)_C < (E_g)_Si

Solution

The allotrope of C (diamond) is an insulator.
(Eg)_C > (Eg)_Si

User

Question Analysis

Correct -
Wrong -
Skipped -

My Perfomance

Score
-
out of -
Rank
-
out of -

Re-Attempt Weekly Quiz Competition

Electronic Devices and Communication Systems Test - 1

Result

Electronic Devices and Communication Systems Test - 1

Score

-

Rank

-

SHARING IS CARING

Question 1

amplification of particular frequency emitted by the system

population inversion

stimulated emission

All of the above

Solution

Question 2

positive

negative

neutral

It depends on the concentration of p impurities.

Solution

Question 3

zero

infinite

0.7eV to 1.3eV

>5eV

Solution

Question 4

Substances with energy gap of the order of 10 eV are insulators.

The conductivity of a semiconductor increases with increase in temperature.

In conductors, the valence and conduction bands may overlap.

The resistivity of a semiconductor increases with increase in temperature.

Solution

Question 5

When we heat a semiconductor, its resistance increases.

When we heat a semiconductor, its resistance decreases.

When we cool a semiconductor to 0 K, it becomes a superconductor.

Resistance of a semiconductor is independent of temperature.

Solution

Question 6

At a very low temperature, it behaves like an insulator.

At high temperatures, two types of charge carriers will cause conductivity.

The charge carriers are all electrons and holes in the valence band at higher temperatures.

It is electrically neutral.

Solution

Question 7

(Eg)C > (Eg)Si

(Eg)C = (Eg)Si

(Eg)C < (Eg)Ge

(Eg)C < (Eg)Si

Solution

User

Question Analysis

My Perfomance

Score

-

Rank

-

Results Announcement on: coming Monday

Stay Tuned: We’ll update you on your result via email or SMS.

(E_g)_C > (E_g)_Si

(E_g)_C = (E_g)_Si

(E_g)_C < (E_g)_Ge

(E_g)_C < (E_g)_Si