Statement (I): The temperature coefficient of | vedclass

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(A) Statement $(I)$: For most pure metals, the resistance increases with temperature, making the temperature coefficient of resistance positive. Thus,

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Statements $I, II, III$ are true.

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(A) Statement $(I)$: For most pure metals, the resistance increases with temperature, making the temperature coefficient of resistance positive. Thus, $(I)$ is true.Statement $(II)$: Given diameter $d = 2 \ mm$, radius $r = 1 \ mm = 10^{-3} \ m$. Area $A = \pi r^2 = \pi 	imes (10^{-3})^2 = \pi 	imes 10^{-6} \ m^2$. Charge $q = 360 \pi \ C$, time $t = 2 \ hours = 7200 \ s$. Current $i = q/t = 360 \pi / 7200 = \pi / 20 \ A$. Electron density $n = 5 	imes 10^{22} \ cm^{-3} = 5 	imes 10^{28} \ m^{-3}$. Drift velocity $v_d = i / (neA) = (\pi / 20) / (5 	imes 10^{28} 	imes 1.6 	imes 10^{-19} 	imes \pi 	imes 10^{-6}) = 1 / (20 	imes 5 	imes 1.6 	imes 10^3) = 1 / (160000) = 6.25 	imes 10^{-6} \ m/s$. Thus, $(II)$ is true.Statement $(III)$: Semiconductors are non-ohmic conductors; they do not follow a linear $V-I$ relationship for all electric field values. Thus, $(III)$ is true.

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