# NEET (NTA)-National Eligibility cum Entrance Test (Medical) Physics: Questions 1690 - 1695 of 2184

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## Question number: 1690

Edit
Assertion-Reason▾

### Assertion (Ꭺ)

The logic gate NOT cannot be built by using diode.

### Reason (Ꭱ)

The output voltage and the input voltage of the diode have 180° phase difference.

### Choices

Choice (4) Response

a.

Both Ꭺ and Ꭱ are true but Ꭱ is NOT the correct explanation of Ꭺ

b.

Both Ꭺ and Ꭱ are true and Ꭱ is the correct explanation of Ꭺ

c.

Ꭺ is true but Ꭱ is false

d.

Ꭺ is false but Ꭱ is true

## Question number: 1691

Edit
MCQ▾

### Question

What will be the input of A and B for the Boolean expression

### Choices

Choice (4) Response

a.

1,0

b.

1,1

c.

0,1

d.

0,0

## 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. Relation between the Valence Bond and Conduction Bond Understanding the changes in the Fermi energy of the semiconductor

## Question number: 1692 (1 of 3 Based on Passage) Show Passage

Edit
MCQ▾

### Question

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

### Choices

Choice (4) Response

a.

0.008

b.

8.2

c.

0.08

d.

0.824

## Question number: 1693 (2 of 3 Based on Passage) Show Passage

Edit
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.

4.79 ⨯ 10 -10

b.

4 ⨯ 10 -10

c.

3.42 ⨯ 10 -11

d.

5.20 ⨯ 10 -12

## Question number: 1694 (3 of 3 Based on Passage) Show Passage

Edit
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.

1.40 ⨯ 10 -2

b.

10.5 ⨯ 10 -2

c.

5.20 ⨯ 10 -2

d.

14 ⨯ 10 -2

## Question number: 1695

Edit
MCQ▾

### Question

 P Q X 0 0 0 0 1 0 1 0 0 1 1 1

### Choices

Choice (4) Response

a.

OR

b.

NOR

c.

NAND

d.

AND