A silver wire has a temperature coefficient of resistivity 4 × 10 - 3 ° C - 1 and its resistance at 20 ° C is 10 Ω . Neglecting any change in dimensions due to the change in temperature, its resistance at 40 ° C is

Question

A silver wire has a temperature coefficient of resistivity 4 × 10 - 3 ° C - 1 and its resistance at 20 ° C is 10 Ω . Neglecting any change in dimensions due to the change in temperature, its resistance at 40 ° C is, 0.8 Ω, 1.8 Ω, 10.8 Ω, 11.6 Ω

MARKS App · Accepted Answer

Given, α = 4 × 10 - 3 ° C - 1 T 1 = 20 ° C T 2 = 40 ° C R ( t 2 ) = R ( t 1 ) ( 1 + a Δ t ) ∆ T = 40 -20 = 20 ° C R ( t 1 ) = 10 Ω R ( 40 ° C ) = 10 ( 1 + 4 × 10 − 3 × 20 ) Ω = 10 1 + 80 × 10 - 3 = 10 1.08 = 10.8 Ω

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