Temperature dependence of resistivity \(\rho(T)\) of semiconductors, insulators, and metals is significantly based on the following factors:

(a) number of charge carriers can change with temperature \(T\).
(b) the time interval between two successive collisions can depend on \(T\).
(c) length of material can be a function of \(T\).
(d) mass of carriers is a function of \(T\).

Which of the above statements is correct?

1. (a, b) 2. (c, d)
3. (b, c) 4. (b, d)
Subtopic:  Derivation of Ohm's Law |
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A metal rod of length 10 cm and a rectangular cross-section of  \(1~ \text {cm} \times 1/2~ \text {cm}\) is connected to a battery across opposite faces. The resistance will be:

1. maximum when the battery is connected across\(1~ \text {cm} \times 1/2~ \text {cm}\) faces.
2. maximum when the battery is connected across \(10~ \text {cm} \times 1~ \text {cm}\) faces.
3. maximum when the battery is connected across \(10~ \text {cm} \times 1/2~ \text {cm}\) faces.
4. same irrespective of the three faces.

Subtopic:  Derivation of Ohm's Law |
 57%
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