# Electronic Devices-Semiconductors (NEET (NTA)-National Eligibility cum Entrance Test (Medical) Physics): Questions 19 - 23 of 23

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## Question number: 19

» Electronic Devices » Semiconductors

MCQ▾

### Question

The energy gap for diamond is nearly

### Choices

Choice (4) Response

a.

2 eV

b.

1 eV

c.

6 eV

d.

4 eV

## Question number: 20

» Electronic Devices » Semiconductors

MCQ▾

### Question

The intrinsic semiconductor becomes an insulator at

### Choices

Choice (4) Response

a.

-100°C

b.

0 K

c.

0°C

d.

300 K

## Passage

Doping changes the Fermi energy of a semiconductor. Consider silicon, with a gap of 1.11 eV between the top of the valence bond and the bottom of the conduction band. At 300K the Fermi level of the pure material is nearly at the mid-point of the gap. Suppose that silicon is doped with donor atoms, each of which has a state 0.15 eV below the bottom of the silicon conduction band, and suppose further that doping raises the Fermi level to 0.11 eV below the bottom of that band.

## Question number: 21 (1 of 3 Based on Passage) Show Passage

» Electronic Devices » Semiconductors

MCQ▾

### Question

Calculate the probability that a donor state in the doped material is occupied?

### Choices

Choice (4) Response

a.

0.008

b.

0.824

c.

8.2

d.

0.08

## Question number: 22 (2 of 3 Based on Passage) Show Passage

» Electronic Devices » Semiconductors

MCQ▾

### Question

For pure silicon, calculate the probability that a state at the bottom of the silicon conduction band is occupied? (e 21.46 = 20.89 ⨯ 10 8)

### Choices

Choice (4) Response

a.

4 ⨯ 10 -10

b.

4.79 ⨯ 10 -10

c.

5.20 ⨯ 10 -12

d.

3.42 ⨯ 10 -11

## Question number: 23 (3 of 3 Based on Passage) Show Passage

» Electronic Devices » Semiconductors

MCQ▾

### Question

For doped silicon, calculate the probability that a state at the bottom of the silicon conduction band is occupied? (e 4.254 = 70.38)

### Choices

Choice (4) Response

a.

10.5 ⨯ 10 -2

b.

1.40 ⨯ 10 -2

c.

14 ⨯ 10 -2

d.

5.20 ⨯ 10 -2

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