Q. If the resistance of a conductor is $5\Omega$ at $50℃$ and $7\Omega$ at $100℃$ then the mean temperature coefficient of resistance of the material is
A) $0.008/℃$
B) $0..006/℃$
C) $0.004/℃$
D) $0.001/℃$
Explanation
(a) Using $R_{T_{2}} = R_{T_{1}}\lbrack 1 + \alpha(T_{2} - T_{1})\rbrack$
$\Rightarrow R_{100} = R_{50}\lbrack 1 + \alpha(100 - 50)\rbrack$
$\Rightarrow 7 = 5\left\lbrack 1 + (\alpha \times 50) \right\rbrack \Rightarrow \alpha = \frac{(7 - 5)}{250} = 0.008/℃$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.