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A wire has a resistance of 3.1Ω at 30ºC and a resistance 4.5Ω at 100ºC. The temperature coefficient of resistance of the wire
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- 0.0064ºC–1
- 0.0034ºC–1
- 0.0025ºC–1
- 0.0012ºC–1
Correct Option: A
R1 = 3.1 Ω at t = 30°C
R2 = 4.5 Ω at t = 100°C
We have, R = R0 (1 + αt)
∴ R1 = R0 [1 + α (30)]
R2 = R0 [1 + α (100)]
| ⇒ | R1 | = | 1 + 30α | |
| R2 | 1 + 100α |
| ⇒ | 3.1 | = | 1 + 30α | ⇒ α = 0.0064 °C-1 |
| 4.5 | 1 + 100α |
