The band gap between the valence band and the conduction band in a certain material is \(3\) eV. What is the longest wavelength of light that can create an electron-hole pair in the material, with the electron in the conduction band and the hole in the valence band? (Take \(hc\)=\(1240\) eV-nm.)
1. \(414\) nm
2. \(300\) nm
3. \(830\) nm
4. \(207\) nm
Subtopic:  Energy Band theory |
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The energy band gap of semiconducting material to produce violet (wavelength \(=4000~\mathring{\text{A}}\)) LED is (nearly):
1. \(3~\text{eV}\)
2. \(5~\text{eV}\)
3. \(1~\text{eV}\)
4. \(7~\text{eV}\)
Subtopic:  Energy Band theory |
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When semiconductor is heated, its resistance:
 
1. decreases
2. increases
3. remains the same
4. may increase or decrease depending on the semiconductor
Subtopic:  Energy Band theory |
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Specify which of the following type of material might satisfy these descriptions:
A half-filled valence band, an empty conduction band, and an energy gap of \(1\) eV.
1. conductor
2. insulator
3. semiconductor
4. none of the above

 
Subtopic:  Energy Band theory |
 79%
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In a good conductor, the energy gap between the conduction band and the valence band is
1. Infinite
2. Wide
3. Narrow
4. Zero

Subtopic:  Energy Band theory |
 77%
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NEET 2023 - Target Batch - Aryan Raj Singh
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Identify the incorrect 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 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 |
 78%
From NCERT
AIPMT - 2005
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NEET 2023 - Target Batch - Aryan Raj Singh
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In the energy band diagram of a material shown below, the open circles and filled circles denote holes and electrons respectively. The material is a/an: 


     

1. p-type semiconductor
2. insulator
3. metal
4. n-type semiconductor

Subtopic:  Energy Band theory |
 75%
From NCERT
AIPMT - 2007
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NEET 2023 - Target Batch - Aryan Raj Singh
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NEET 2023 - Target Batch - Aryan Raj Singh

A semiconductor has a negative temperature coefficient of:
 
1. resistance
2. conductance
3. both resistance and conductance
4. neither resistance nor conductance
Subtopic:  Energy Band theory |
 75%
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Carbon, Silicon, and Germanium atoms have four valence electrons each. Their valence and conduction bands are separated by energy gaps represented by \(\left(E_g\right)_C,(E_g)_{Si}~\text{and}~(E_g)_{Ge}\) respectively. Which one of the following relationships is true in their case?

1. \(\left(E_g\right)_C<\left(E_g\right)_{G e} \) 2. \(\left(E_g\right)_C>\left(E_g\right)_{S i} \)
3. \(\left(E_g\right)_C=\left(E_g\right)_{S i} \) 4. \(\left(E_g\right)_C<\left(E_g\right)_{S i}\)
Subtopic:  Energy Band theory |
 71%
From NCERT
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As the temperature increases, the electrical resistance:
1. decreases for conductors but increases for semiconductors.
2. increases for both conductors and semiconductors.
3. decreases for both conductors and semiconductors.
4. increases for conductors but decreases for semiconductors.
Subtopic:  Energy Band theory |
 71%
From NCERT
NEET - 2022
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NEET 2023 - Target Batch - Aryan Raj Singh
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