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Semiconductor Electronics Material Devices and Simple Circuits

150697 In a p-n junction, potential barrier of $200 meV$ exists across the junction. A hole with a kinetic energy of $300 meV$ approaches the junction. Let $E_{1}$ and $E_{2}$ be kinetic energies of the hole when it crosses the junction, while it approaches the junction from the $p$ -side and $n$ side respectively : The value of $\frac{E_{2}}{E_{1}}$ is

1 0.2

2 5.0

3 1

4 1.5

Explanation:

B Given that,
Barrier potential $= 200 meV$
Kinetic energy of Hole (KE) $= 300 meV$
When junction is forward bias the energy increases
$∴ E_{2} = 300 + 200 = 500 meV$
When junction is reversed bias then energy in decreases,
So,
$E_{1} = 300 - 200 = 100 meV$
$∴ \frac{E_{2}}{E_{1}} = \frac{500 meV}{100 meV}$
$\frac{E_{2}}{E_{1}} = 5$

TS EAMCET 31.07.2022

Semiconductor Electronics Material Devices and Simple Circuits

150698 Assertion: An N-type semiconductor has a large number of electrons but still it is electrically neutral.
Reason: An N-type semiconductor is obtained by doping an intrinsic semiconductor with a pentavalent impurity.

1 If both assertion and reason are true and reason is the correct explanation of assertion.

2 If both assertion and reason are true but reason is not the correct explanation of assertion.

3 If assertion is true but reason is false.

4 If both assertion and reason are false.

Explanation:

B When an N-type semiconductor is made by doping pure germanium or silicon crystals with suitable impurity atoms of five valence electron. Since suitable impurity atoms take the position of $Ge$ atom in germanium crystal, its four electrons from covalent bond by sharing electrons with the neighboring four atoms of germanium where as the fifth electron is left free. Since the atom on the whole is electrically neutral, the n-type semiconductor is also neutral.

AIIMS-26.05.2019(M) Shift-1

Semiconductor Electronics Material Devices and Simple Circuits

150473 Which of the following statements is true?

1 A solid is an insulator or semiconductor, if its conduction band is partially filled

2 A solid is necessarily an insulator, if its conduction band is empty

3 A solid is necessarily a semiconductor, if its conduction band is empty

4 A solid is a conductor, if its conduction band is partially filled

TS- EAMCET-05.05.2018

Semiconductor Electronics Material Devices and Simple Circuits

150476 'The dominant contribution to current comes from holes in case of

1 metals

2 intrinsic semiconductors

3 p-type extrinsic semiconductors

4 n-type extrinsic semiconductors

Manipal UGET-2019

Semiconductor Electronics Material Devices and Simple Circuits

150484 The electrical conductivity of semiconductors

1 does not depend upon temperature

2 increases with rise in temperature

3 decreases with rise in temperature

4 first decreases and the increases with rise in temperature

Explanation:

B Electrical conductivity of semiconductors increases with increase in temperature.
- Semiconductor follow NTC, means temperature increases- resistivity ( $ρ$ ) decreases-conductivity $(σ)$ increases.
Conductivity $(σ)$ is reciprocal of resistivity $(ρ)$
Conductivity represent current carrying capacity of the material or device are called conductivity.
$σ = nq μ$
Where, $σ =$ conductivity
$n =$ carrier density
$q =$ electric charge
$μ =$ mobility

CG PET- 2013

Semiconductor Electronics Material Devices and Simple Circuits

150697 In a p-n junction, potential barrier of $200 meV$ exists across the junction. A hole with a kinetic energy of $300 meV$ approaches the junction. Let $E_{1}$ and $E_{2}$ be kinetic energies of the hole when it crosses the junction, while it approaches the junction from the $p$ -side and $n$ side respectively : The value of $\frac{E_{2}}{E_{1}}$ is

1 0.2

2 5.0

3 1

4 1.5

Explanation:

B Given that,
Barrier potential $= 200 meV$
Kinetic energy of Hole (KE) $= 300 meV$
When junction is forward bias the energy increases
$∴ E_{2} = 300 + 200 = 500 meV$
When junction is reversed bias then energy in decreases,
So,
$E_{1} = 300 - 200 = 100 meV$
$∴ \frac{E_{2}}{E_{1}} = \frac{500 meV}{100 meV}$
$\frac{E_{2}}{E_{1}} = 5$

TS EAMCET 31.07.2022

Semiconductor Electronics Material Devices and Simple Circuits

150698 Assertion: An N-type semiconductor has a large number of electrons but still it is electrically neutral.
Reason: An N-type semiconductor is obtained by doping an intrinsic semiconductor with a pentavalent impurity.

1 If both assertion and reason are true and reason is the correct explanation of assertion.

2 If both assertion and reason are true but reason is not the correct explanation of assertion.

3 If assertion is true but reason is false.

4 If both assertion and reason are false.

Explanation:

B When an N-type semiconductor is made by doping pure germanium or silicon crystals with suitable impurity atoms of five valence electron. Since suitable impurity atoms take the position of $Ge$ atom in germanium crystal, its four electrons from covalent bond by sharing electrons with the neighboring four atoms of germanium where as the fifth electron is left free. Since the atom on the whole is electrically neutral, the n-type semiconductor is also neutral.

AIIMS-26.05.2019(M) Shift-1

Semiconductor Electronics Material Devices and Simple Circuits

150473 Which of the following statements is true?

1 A solid is an insulator or semiconductor, if its conduction band is partially filled

2 A solid is necessarily an insulator, if its conduction band is empty

3 A solid is necessarily a semiconductor, if its conduction band is empty

4 A solid is a conductor, if its conduction band is partially filled

TS- EAMCET-05.05.2018

Semiconductor Electronics Material Devices and Simple Circuits

150476 'The dominant contribution to current comes from holes in case of

1 metals

2 intrinsic semiconductors

3 p-type extrinsic semiconductors

4 n-type extrinsic semiconductors

Manipal UGET-2019

Semiconductor Electronics Material Devices and Simple Circuits

150484 The electrical conductivity of semiconductors

1 does not depend upon temperature

2 increases with rise in temperature

3 decreases with rise in temperature

4 first decreases and the increases with rise in temperature

Explanation:

B Electrical conductivity of semiconductors increases with increase in temperature.
- Semiconductor follow NTC, means temperature increases- resistivity ( $ρ$ ) decreases-conductivity $(σ)$ increases.
Conductivity $(σ)$ is reciprocal of resistivity $(ρ)$
Conductivity represent current carrying capacity of the material or device are called conductivity.
$σ = nq μ$
Where, $σ =$ conductivity
$n =$ carrier density
$q =$ electric charge
$μ =$ mobility

CG PET- 2013

Semiconductor Electronics Material Devices and Simple Circuits

150697 In a p-n junction, potential barrier of $200 meV$ exists across the junction. A hole with a kinetic energy of $300 meV$ approaches the junction. Let $E_{1}$ and $E_{2}$ be kinetic energies of the hole when it crosses the junction, while it approaches the junction from the $p$ -side and $n$ side respectively : The value of $\frac{E_{2}}{E_{1}}$ is

1 0.2

2 5.0

3 1

4 1.5

Explanation:

B Given that,
Barrier potential $= 200 meV$
Kinetic energy of Hole (KE) $= 300 meV$
When junction is forward bias the energy increases
$∴ E_{2} = 300 + 200 = 500 meV$
When junction is reversed bias then energy in decreases,
So,
$E_{1} = 300 - 200 = 100 meV$
$∴ \frac{E_{2}}{E_{1}} = \frac{500 meV}{100 meV}$
$\frac{E_{2}}{E_{1}} = 5$

TS EAMCET 31.07.2022

Semiconductor Electronics Material Devices and Simple Circuits

150698 Assertion: An N-type semiconductor has a large number of electrons but still it is electrically neutral.
Reason: An N-type semiconductor is obtained by doping an intrinsic semiconductor with a pentavalent impurity.

1 If both assertion and reason are true and reason is the correct explanation of assertion.

2 If both assertion and reason are true but reason is not the correct explanation of assertion.

3 If assertion is true but reason is false.

4 If both assertion and reason are false.

Explanation:

B When an N-type semiconductor is made by doping pure germanium or silicon crystals with suitable impurity atoms of five valence electron. Since suitable impurity atoms take the position of $Ge$ atom in germanium crystal, its four electrons from covalent bond by sharing electrons with the neighboring four atoms of germanium where as the fifth electron is left free. Since the atom on the whole is electrically neutral, the n-type semiconductor is also neutral.

AIIMS-26.05.2019(M) Shift-1

Semiconductor Electronics Material Devices and Simple Circuits

150473 Which of the following statements is true?

1 A solid is an insulator or semiconductor, if its conduction band is partially filled

2 A solid is necessarily an insulator, if its conduction band is empty

3 A solid is necessarily a semiconductor, if its conduction band is empty

4 A solid is a conductor, if its conduction band is partially filled

TS- EAMCET-05.05.2018

Semiconductor Electronics Material Devices and Simple Circuits

150476 'The dominant contribution to current comes from holes in case of

1 metals

2 intrinsic semiconductors

3 p-type extrinsic semiconductors

4 n-type extrinsic semiconductors

Manipal UGET-2019

Semiconductor Electronics Material Devices and Simple Circuits

150484 The electrical conductivity of semiconductors

1 does not depend upon temperature

2 increases with rise in temperature

3 decreases with rise in temperature

4 first decreases and the increases with rise in temperature

Explanation:

B Electrical conductivity of semiconductors increases with increase in temperature.
- Semiconductor follow NTC, means temperature increases- resistivity ( $ρ$ ) decreases-conductivity $(σ)$ increases.
Conductivity $(σ)$ is reciprocal of resistivity $(ρ)$
Conductivity represent current carrying capacity of the material or device are called conductivity.
$σ = nq μ$
Where, $σ =$ conductivity
$n =$ carrier density
$q =$ electric charge
$μ =$ mobility

CG PET- 2013

Semiconductor Electronics Material Devices and Simple Circuits

150697 In a p-n junction, potential barrier of $200 meV$ exists across the junction. A hole with a kinetic energy of $300 meV$ approaches the junction. Let $E_{1}$ and $E_{2}$ be kinetic energies of the hole when it crosses the junction, while it approaches the junction from the $p$ -side and $n$ side respectively : The value of $\frac{E_{2}}{E_{1}}$ is

1 0.2

2 5.0

3 1

4 1.5

Explanation:

B Given that,
Barrier potential $= 200 meV$
Kinetic energy of Hole (KE) $= 300 meV$
When junction is forward bias the energy increases
$∴ E_{2} = 300 + 200 = 500 meV$
When junction is reversed bias then energy in decreases,
So,
$E_{1} = 300 - 200 = 100 meV$
$∴ \frac{E_{2}}{E_{1}} = \frac{500 meV}{100 meV}$
$\frac{E_{2}}{E_{1}} = 5$

TS EAMCET 31.07.2022

Semiconductor Electronics Material Devices and Simple Circuits

150698 Assertion: An N-type semiconductor has a large number of electrons but still it is electrically neutral.
Reason: An N-type semiconductor is obtained by doping an intrinsic semiconductor with a pentavalent impurity.

1 If both assertion and reason are true and reason is the correct explanation of assertion.

2 If both assertion and reason are true but reason is not the correct explanation of assertion.

3 If assertion is true but reason is false.

4 If both assertion and reason are false.

Explanation:

B When an N-type semiconductor is made by doping pure germanium or silicon crystals with suitable impurity atoms of five valence electron. Since suitable impurity atoms take the position of $Ge$ atom in germanium crystal, its four electrons from covalent bond by sharing electrons with the neighboring four atoms of germanium where as the fifth electron is left free. Since the atom on the whole is electrically neutral, the n-type semiconductor is also neutral.

AIIMS-26.05.2019(M) Shift-1

Semiconductor Electronics Material Devices and Simple Circuits

150473 Which of the following statements is true?

1 A solid is an insulator or semiconductor, if its conduction band is partially filled

2 A solid is necessarily an insulator, if its conduction band is empty

3 A solid is necessarily a semiconductor, if its conduction band is empty

4 A solid is a conductor, if its conduction band is partially filled

TS- EAMCET-05.05.2018

Semiconductor Electronics Material Devices and Simple Circuits

150476 'The dominant contribution to current comes from holes in case of

1 metals

2 intrinsic semiconductors

3 p-type extrinsic semiconductors

4 n-type extrinsic semiconductors

Manipal UGET-2019

Semiconductor Electronics Material Devices and Simple Circuits

150484 The electrical conductivity of semiconductors

1 does not depend upon temperature

2 increases with rise in temperature

3 decreases with rise in temperature

4 first decreases and the increases with rise in temperature

Explanation:

B Electrical conductivity of semiconductors increases with increase in temperature.
- Semiconductor follow NTC, means temperature increases- resistivity ( $ρ$ ) decreases-conductivity $(σ)$ increases.
Conductivity $(σ)$ is reciprocal of resistivity $(ρ)$
Conductivity represent current carrying capacity of the material or device are called conductivity.
$σ = nq μ$
Where, $σ =$ conductivity
$n =$ carrier density
$q =$ electric charge
$μ =$ mobility

CG PET- 2013

Semiconductor Electronics Material Devices and Simple Circuits

150697 In a p-n junction, potential barrier of $200 meV$ exists across the junction. A hole with a kinetic energy of $300 meV$ approaches the junction. Let $E_{1}$ and $E_{2}$ be kinetic energies of the hole when it crosses the junction, while it approaches the junction from the $p$ -side and $n$ side respectively : The value of $\frac{E_{2}}{E_{1}}$ is

1 0.2

2 5.0

3 1

4 1.5

Explanation:

B Given that,
Barrier potential $= 200 meV$
Kinetic energy of Hole (KE) $= 300 meV$
When junction is forward bias the energy increases
$∴ E_{2} = 300 + 200 = 500 meV$
When junction is reversed bias then energy in decreases,
So,
$E_{1} = 300 - 200 = 100 meV$
$∴ \frac{E_{2}}{E_{1}} = \frac{500 meV}{100 meV}$
$\frac{E_{2}}{E_{1}} = 5$

TS EAMCET 31.07.2022

Semiconductor Electronics Material Devices and Simple Circuits

150698 Assertion: An N-type semiconductor has a large number of electrons but still it is electrically neutral.
Reason: An N-type semiconductor is obtained by doping an intrinsic semiconductor with a pentavalent impurity.

1 If both assertion and reason are true and reason is the correct explanation of assertion.

2 If both assertion and reason are true but reason is not the correct explanation of assertion.

3 If assertion is true but reason is false.

4 If both assertion and reason are false.

Explanation:

B When an N-type semiconductor is made by doping pure germanium or silicon crystals with suitable impurity atoms of five valence electron. Since suitable impurity atoms take the position of $Ge$ atom in germanium crystal, its four electrons from covalent bond by sharing electrons with the neighboring four atoms of germanium where as the fifth electron is left free. Since the atom on the whole is electrically neutral, the n-type semiconductor is also neutral.

AIIMS-26.05.2019(M) Shift-1

Semiconductor Electronics Material Devices and Simple Circuits

150473 Which of the following statements is true?

1 A solid is an insulator or semiconductor, if its conduction band is partially filled

2 A solid is necessarily an insulator, if its conduction band is empty

3 A solid is necessarily a semiconductor, if its conduction band is empty

4 A solid is a conductor, if its conduction band is partially filled

TS- EAMCET-05.05.2018

Semiconductor Electronics Material Devices and Simple Circuits

150476 'The dominant contribution to current comes from holes in case of

1 metals

2 intrinsic semiconductors

3 p-type extrinsic semiconductors

4 n-type extrinsic semiconductors

Manipal UGET-2019

Semiconductor Electronics Material Devices and Simple Circuits

150484 The electrical conductivity of semiconductors

1 does not depend upon temperature

2 increases with rise in temperature

3 decreases with rise in temperature

4 first decreases and the increases with rise in temperature

Explanation:

B Electrical conductivity of semiconductors increases with increase in temperature.
- Semiconductor follow NTC, means temperature increases- resistivity ( $ρ$ ) decreases-conductivity $(σ)$ increases.
Conductivity $(σ)$ is reciprocal of resistivity $(ρ)$
Conductivity represent current carrying capacity of the material or device are called conductivity.
$σ = nq μ$
Where, $σ =$ conductivity
$n =$ carrier density
$q =$ electric charge
$μ =$ mobility

CG PET- 2013