Question

A metallic wire has a resistance of 120

Ω at 20°. Find the temperature at which the

resistance of same metallic wire rises to 240

Ω where the temperature coefficient of the

wire is 2 × 10−40−1​

Answer 1

5020∘C

Explanation:

Given R1=R20=120Ω,R2=R1=240Ω,t=?,

α=2×10−40C−1t1=20∘C,t2=T=?

Formular used to find the temperature coefficient of

resistance is

α=R2−R1R1(t2−t1)=RT−R20R20(T−20)

2×10−4=240−120120(T−20)

T−20=120120×2×10−4

T=12×10−4+20=0.5×104+20= 5020∘C