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Physics · 2024 · 2 marks
CBSE 2024 · Region 2 · Set 1 · Q17
Define resistivity of a conductor. How does the resistivity of a conductor depend upon the following: (a) Number density of free electrons in the…
Define resistivity of a conductor. How does the resistivity of a conductor depend upon the following:
(a)
Number density of free electrons in the conductor (n)
(b)
Their relaxation time $\displaystyle (\tau)$
Marking-scheme solution
Resistance offered by a material of unit length and having unit cross-sectional area is called resistivity.
$\displaystyle \rho=\frac{m}{n e^{2} \tau}$
(a)
$\displaystyle \rho \propto \frac{1}{n}$
(b)
$\displaystyle \rho \propto \frac{1}{\tau}$
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