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A copper rod length 1 am and area of cro...

A copper rod length 1 am and area of cross - section `0.1" m"^(2)` has its end maintained at `100^(@)C` by means of 0.4 KW electric heater. What is temperature of other end in steady state ? `(K=400W//mK)` :

A

`90^(@)C`

B

`100^(@)C`

C

`70^(@)C`

D

None of the above

Text Solution

Verified by Experts

The correct Answer is:
A
Temp. of `100^(@)C` is maintained if lost second is `0.4` in kW.
i.e `(Q)/(t)=0.4xx10^(3)`
If T be the temperature of other end of rod
then `("k A"(100-T))/(d)=0.4xx10^(3)`
`(400xx0.1xx(100-T))/(1)=0.4xx10^(3)`
`rArrT=90^(@)C`
Hence correct choice is (a).
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Knowledge Check

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