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^-4​

Answer 1

Explanation:

Given data:

resistance Rref=120 ohm

Temperature Tref=20°C

resistance R= 240 ohm

T=?

temperature co.eff. of wire=2*10^-4.

Solution:

formula is

R=Rref[1+temperature co.eff. of wire(T-Tref)]

by substituting given data

240=120(1+2*10^-4(T-20))

2=1+2*10^-4(T-20))

1=2*10^-4(T-20)

0.5*10^4=T-20

1000=T-20

T=1000+20=1020°C.

answer is 1020°C