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Q. No.The forbidden energy band gaps in conductors, semiconductors and insulators are \(EG_{1},\) \(EG_{2}\) and \(EG_{3}\) respectively. The relation among them is:
1. \(EG_{1}=EG_{2}=EG_{3}\)
2. \(EG_{1}<EG_{2}<EG_{3}\)
3. \(EG_{1}>EG_{2}>EG_{3}\)
4. \(EG_{1}<EG_{2}>EG_{3}\)
1. \(EG_{1}=EG_{2}=EG_{3}\)
2. \(EG_{1}<EG_{2}<EG_{3}\)
3. \(EG_{1}>EG_{2}>EG_{3}\)
4. \(EG_{1}<EG_{2}>EG_{3}\)
Subtopic: Energy Band theory |
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Choose the only false statement from the following.
| 1. | The resistivity of a semiconductor increases with an increase in temperature. |
| 2. | Substances with an energy gap of the order of \(10~\text{eV}\) are insulators. |
| 3. | In conductors, the valence and conduction bands may overlap. |
| 4. | The conductivity of a semiconductor increases with an increase in temperature. |
Subtopic: Energy Band theory |
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The electrical conductivity of a semiconductor increases when electromagnetic radiation with a wavelength shorter than \(2400~\text{nm}\) is incident on it. The band gap of the semiconductor (in eV) is: \((h=6.63\times10^{-34}~\text{J-s})\)
| 1. | \(0.33\) eV | 2. | \(0.80\) eV |
| 3. | \(0.52\) eV | 4. | \(0.10\) eV |
Subtopic: Energy Band theory |
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Level 2: 60%+
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The maximum wavelength of electromagnetic radiation, which can create hole-electron pairs in semiconductor is:
(Given that the forbidden energy gap in the semiconductor is \(0.5~\text{eV}\))
1. \(2.48 \times 10^{-7}~\text{m} \)
2. \(2.48 \times 10^{-6}~\text{m} \)
3. \(2.48 \times 10^{-8}~\text{m}\)
4. \(2.48 \times 10^{-9}~\text{m}\)
(Given that the forbidden energy gap in the semiconductor is \(0.5~\text{eV}\))
1. \(2.48 \times 10^{-7}~\text{m} \)
2. \(2.48 \times 10^{-6}~\text{m} \)
3. \(2.48 \times 10^{-8}~\text{m}\)
4. \(2.48 \times 10^{-9}~\text{m}\)
Subtopic: Energy Band theory |
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The dominant contribution to current comes from holes in the case of:
| 1. | metals |
| 2. | intrinsic semiconductors |
| 3. | \(\mathrm{p} \text-\)type extrinsic semiconductors |
| 4. | \(\mathrm{n} \text-\)type extrinsic semiconductors |
Subtopic: Types of Semiconductors |
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An \(\mathrm{n\text-}\)type semiconductor is formed by adding which of the following impurity materials:
| 1. | aluminum, boron, or selenium |
| 2. | aluminum, boron, or indium |
| 3. | phosphorus, antimony, or arsenic |
| 4. | cobalt, aluminum, or selenium |
Subtopic: Types of Semiconductors |
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Subtopic: Types of Semiconductors |
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Conductivity in semiconductors is due to:
| 1. | holes only | 2. | electrons only |
| 3. | both electrons and holes | 4. | neither electrons nor holes |
Subtopic: Types of Semiconductors |
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The impurity atoms with which pure silicon may be doped to make it a \(\mathrm{p\text{-}}\)type semiconductor are those of:
Then choose the correct option:
| (a) | phosphorus | (b) | boron |
| (c) | antimony | (d) | aluminium |
| 1. | (a), (b) | 2. | (b), (d) |
| 3. | (a), (c) | 4. | (a), (d) |
Subtopic: Types of Semiconductors |
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At absolute zero temperature, the semiconductor acts as a/an:
1. conductor
2. superconductor
3. semiconductor having large conductivity
4. insulator
1. conductor
2. superconductor
3. semiconductor having large conductivity
4. insulator
Subtopic: Types of Semiconductors |
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