Question:
The resistance of a conductor at $15^{\circ} \mathrm{C}$ is $16 \Omega$ and at $100^{\circ} \mathrm{C}$ is $20 \Omega$. What will be the temperature coefficient of resistance of the conductor?
Correct Option: , 3
Solution:
$16=\mathrm{R}_{0}\left[1+\alpha\left(15-\mathrm{T}_{\mathrm{o}}\right)\right]$
$20=\mathrm{R}_{0}\left[1+\alpha\left(100-\mathrm{T}_{\mathrm{o}}\right)\right]$
Assuming $\mathrm{T}_{0}=0^{\circ} \mathrm{C}$, as a general convention.
$\Rightarrow \frac{16}{20}=\frac{1+\alpha \times 15}{1+\alpha \times 100}$
$\Rightarrow \alpha=0.003{ }^{\circ} \mathrm{C}^{-1}$