If a copper wire has a resistance of 23.7 ω at a temperature of 20.3 oc, what resistance does it have at 79.0 oc? (neglect any change in length or cross-sectional area resulting from the change in temperature.)

Explanation:

Resistance ca be determine by using following formula

where

R = Conductor resistance = 23.7Ω

Rref = conductor reistance at reference temperature,

α = temperature coefficient of resistance for material, for copper 40.41*10^{-4}

T = Conductor temperature in Celcius =  20.3°C

Tref = reference temperature at which α  is specified.

now for 79 degree celcius

d) physical means can be used to separate the components of air.