Easy MCQ +4 / -1 PYQ · JEE Mains 2021

The resistance of a conductor at 15$^\circ$C is 16$\Omega$ and at 100$^\circ$C is 20$\Omega$. What will be the temperature coefficient of resistance of the conductor?

  1. A 0.010$^\circ$C<sup>$-$1</sup>
  2. B 0.033$^\circ$C<sup>$-$1</sup>
  3. C 0.003$^\circ$C<sup>$-$1</sup> Correct answer
  4. D 0.042$^\circ$C<sup>$-$1</sup>

Solution

16 = R<sub>0</sub> [1 + $\alpha$ (15 $-$ T<sub>0</sub>)]<br><br>20 = R<sub>0</sub> [1 + $\alpha$ (100 $-$ T<sub>0</sub>)]<br><br>Assuming T<sub>0</sub> = 0$^\circ$C, as a general convention.<br><br>$\Rightarrow$ ${{16} \over {20}} = {{1 + \alpha \times 15} \over {1 + \alpha \times 100}}$<br><br>$\Rightarrow$ $\alpha$ = 0.003$^\circ$C<sup>$-$1</sup>

About this question

Subject: Physics · Chapter: Current Electricity · Topic: Ohm's Law and Resistance

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