Question

The resistance of a coil is 4.2 at 100oc and the temperature coefficient of resistance of its material is 0.004oc. Its resistance will be 4 at

Answer 1

The resistance of a coil is 4.2 Ω at 100°C and the temperature coefficient of resistance of its material is 0.004/°C.

To find : the temperature at which resistance of coil will be 4 Ω.

solution : using formula, R = R₀[1 + α∆T]

here at temperature = T, R₀ = 4

and resistance, R = 4.2 at temperature = 100°C

so, 4.2 = 4[1 + 0.004/°C × (100°C - T)]

⇒4.2 = 4 + 4 × 0.004 × (100 - T)

⇒0.2 = 0.016 × (100 - T)

⇒0.2/0.016 = 100 - T

⇒12.5 = 100 - T

⇒T = 87.5 °C

Therefore the temperature is 87.5°C at which resistance of the coil will be 4 Ω

Answer 2

Answer:

4

Explanation:

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