Semiconductor Class 12th PHYSICS MCQs For NEET JEE IIT

 

1.Which among the following is the most commonly used semiconductor?

A) Silicon
B) Carbon
C) Germanium
D) Sulphur

ANSWER= (A) Silicon

 

2.What happens to the resistance of a pure semiconductor when heated?

A) The resistance increases
B) The resistance decreases
C) The temperature remains the same
D) Can’t say

ANSWER= (B) The resistance decreases

 

3.How many valence electrons does a pentavalent impurity have?

A) 3
B) 4
C) 5
D) 6

ANSWER= (C) 5

 

4. How many valence electrons do trivalent impurities have?

A) 2
B) 3
C) 4
D) 5

ANSWER= (B) 3

 

5. Which of the following is created when trivalent impurities are added to a semiconductor?

A) Free electrons
B) Holes
C) Bound electrons
D) Valence electrons

ANSWER= (B) Holes

 

6. Which of the following does a hole in the semiconductor define?

A) Free proton
B) A free neutron
C) A free-electron
D) An incomplete part of an electron pair bond

ANSWER= (D) An incomplete part of an electron pair bond

 

7. An electron and a hole in close proximity would tend to _____.

A) attract each other
B) repel each other
C) have no effect on each other
D) destroy each other

ANSWER= (A) attract each other

 

8. What is the random motion of free electrons and holes due to thermal agitation called?

A) Pressure
B) Diffusion
C) Ionisation
D) None of the above

ANSWER= (B) Diffusion

 

9. Why is the mobility of free electrons greater than that of holes?

A) They are light
B) They mutually collide less
C) They require low energy to continue the motion
D) They carry negative energy

ANSWER= (C) They require low energy to continue the motion

 

10. The relation between the number of free electrons in semiconductor and its temperature is given as

A) n∝T
B) n∝T2
C) n∝T3/2
D) n∝T−−√

ANSWER= (C) n∝T3/2