$${C}$$ 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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$$\mathrm{p\text-n}$$ 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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A p-n photodiode is made of a material with a bandgap of 2.0 eV. The minimum frequency of the radiation that can be absorbed by the material is nearly:

1. $10×{10}^{14}$ $\mathrm{Hz}$

2. $5×{10}^{14}$ $\mathrm{Hz}$

3. $1×{10}^{14}$ $\mathrm{Hz}$

4. $20×{10}^{14}$ $\mathrm{Hz}$

Subtopic:  Energy Band theory | Applications of PN junction |
81%
From NCERT
AIPMT - 2008
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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 |
72%
From NCERT
AIPMT - 2007
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