Current Electricity 1 Question 18
18. Read the following statements carefully
(1993, 2M)
$Y$ : The resistivity of semiconductor decreases with increase of temperature.
$Z$ : In a conducting solid, the rate of collisions between free electrons and ions increases with increase of temperature.
Select the correct statement (s) from the following
(a) $Y$ is true but $Z$ is false
(b) $Y$ is false but $Z$ is true $\backslash$
(c) Both $Y$ and $Z$ are true
(d) $Y$ is true and $Z$ is the correct reason for $Y$
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Solution:
- Resistivity of conductors increases with increase in temperature because rate of collisions between free electrons and ions increase with increase of temperature. However, the resistivity of semiconductors decreases with increase in temperature, because more and more covalent bonds are broken at higher temperatures.
