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Question
In an extrinsic semiconductor, the number density of holes is 4 × 1020 m-3. If the number density of intrinsic carriers is 1.2 × 1015 m-3, the number density of electrons in it is ______.
Options
1.8 × 109 m-3
2.4 × 1010 m-3
3.6 × 109 m-3
3.2 × 1010 m-3
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Solution
In an extrinsic semiconductor, the number density of holes is 4 × 1020 m-3. If the number density of intrinsic carriers is 1.2 × 1015 m-3, the number density of electrons in it is 3.6 × 109 m-3.
Explanation:
We know that,
Number of density of electrons = `(n_i^2)/(n_h)`
Where, ni is density of intrinsic carrier, nh is the density of holes.
Given:
`n_i = 1.2 xx 10^15` m-3
`n_h = 4 xx 10^20` m-3
`n_e = (n_i^2)/(n_h)`
`n_e = (1.2 xx 10^15)^2/(4 xx 10^20)`
`n_e = 3.6 xx 10^9` m-3
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