# NEET Physics: Questions 1690 - 1695 of 2099

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## Question number: 1690

» Electronic Devices » Logic Gates (Or, and, NOT, NAND and NOR)

### 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. | Ꭺ is false but Ꭱ is true | |

c. | Both Ꭺ and Ꭱ are true and Ꭱ is the correct explanation of Ꭺ | |

d. | Ꭺ is true but Ꭱ is false |

## Question number: 1691

» Electronic Devices » Logic Gates (Or, and, NOT, NAND and NOR)

### Question

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

### Choices

Choice (4) | Response | |
---|---|---|

a. | 0, 0 | |

b. | 1, 0 | |

c. | 1, 1 | |

d. | 0, 1 |

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

» Electronic Devices » Semiconductors

### 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 | |

b. | 4.79 ⨯ 10 | |

c. | 5.20 ⨯ 10 | |

d. | 3.42 ⨯ 10 |

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

» Electronic Devices » Semiconductors

### 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 | |

b. | 1.40 ⨯ 10 | |

c. | 14 ⨯ 10 | |

d. | 5.20 ⨯ 10 |

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

» Electronic Devices » Semiconductors

### 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: 1695

» Electronic Devices » Logic Gates (Or, and, NOT, NAND and NOR)

### Question

P | Q | X |

0 | 0 | 0 |

0 | 1 | 0 |

1 | 0 | 0 |

1 | 1 | 1 |

### Choices

Choice (4) | Response | |
---|---|---|

a. | NOR | |

b. | OR | |

c. | AND | |

d. | NAND |