(a)
Show that the current density
(a)
Answer to Problem 11P
The current density
Explanation of Solution
Write the expression for the current density,
Here,
Write the expression for the drift velocity,
Here,
Write the expression for the drift velocity,
Here,
Compare (II) and (III),
Conclusion:
Substitute (II) and (IV) in (I),
Therefore, the current density
(b)
Show that the both electrons and holes are present when
(b)
Answer to Problem 11P
The both electrons and holes are present when
Explanation of Solution
Write the expression for the current density,
Here,
Write the expression for the current density,
Here,
Write the expression for the current density of the electrons,
Here,
Write the expression for the current density of the holes,
Here,
Conclusion:
Substitute (VII), (VIII) and (IX) in (VI),
Therefore, the both electrons and holes are present when
(c)
The drift speed of an electron .
(c)
Answer to Problem 11P
The drift speed of an electron is
Explanation of Solution
From part (a), the equation (III)
Write the expression for the drift speed of an electron,
Here,
Conclusion:
Substitute
Therefore, the drift speed of an electron is
(d)
The resistivity of sample.
(d)
Answer to Problem 11P
The resistivity of sample is
Explanation of Solution
From part (b), take the equation (X)
Write the expression for the electrical conductivity
Write the expression for the resistivity of sample,
Here,
Conclusion:
Substitute
Substitute
Therefore, the resistivity of sample is
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Chapter 12 Solutions
Modern Physics
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