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. \(\mathrm{p}\text-\)type semiconductor
2. insulator
3. metal
4. \(\mathrm{n}\text-\)type semiconductor
Subtopic:  Energy Band theory |
 74%
From NCERT
AIPMT - 2007
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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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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 |
 69%
From NCERT
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\(\mathrm{p\text-n}\) photodiode is fabricated from a semiconductor with a band gap of \(2.5\) eV. It can detect a signal of wavelength:
1. \(6000~\mathring{A}\)
2. \(4000\) nm
3. \(6000\) nm
4. \(4000~\mathring{A}\)  
Subtopic:  Energy Band theory |
 63%
From NCERT
AIPMT - 2009
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\({C}\) and \({Si}\) both have the same lattice structure, having \(4\) bonding electrons in each. However, \(C\) is an insulator whereas \(Si\) is an intrinsic semiconductor. This is because:
1. in the case of \(C\), the valence band is not completely filled at absolute zero temperature.
2. in the case of \(C\), the conduction band is partly filled even at absolute zero temperature.
3. the four bonding electrons in the case of \(C\) lie in the second orbit, whereas in the case of \(Si\), they lie in the third.
4. the four bonding electrons in the case of \(C\) lie in the third orbit, whereas for \(Si\), they lie in the fourth orbit.
Subtopic:  Energy Band theory |
 71%
From NCERT
NEET - 2012
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