Question

an aluminium wire has resistance of 25 ohm at 20°c.what is the resistance at 50 c .temperature coefficient of copper is 0.00403 at20c​

Answer 1

Answer:

Given : R

T

=60 ohms @ T=500

o

C

Also, R

T

′

=20 ohms @ T

′

=20

o

C

Resistance at a given temperature R

T

=R

T

′

[1+α(T−T

′

)]

∴ 60=20[1+α(500−20)]

⟹ α=

480

2

=0.00417

Let resistance of wire is 25 ohm at temperature T

′′

.

∴ R

T

′′

=R

T

′

[1+α(T

′′

−T

′

)]

OR 25=20[1+(0.00417)(T

′′

−20)]

⟹ T

′′

=80

o

C