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Two insulated metal bars each of length ...


Two insulated metal bars each of length 5 cm and rectangular cross section with sides 2 cm and 3 cm are wedged between two walls, one held at `100^@C` and the other at `0^@C`. The bars are made of lead and silver. `K_(pb)=350 W//mK,K_(Ag)=425W//mK`.
Thermal corrent through lead bar is

A

210 W

B

420 W

C

510 W

D

930 W

Text Solution

Verified by Experts

The correct Answer is:
B
Resistance of lead bar
`R_(pb)=(l_(pb))/(K_(pb)A_(pb))=(5xx10^-2)/(350xx6xx10^-4)`
`=(10)/(21)=(5)/(21)(K)/(W)`
Thermal current through lead bar
`I_(pb)=(DeltaT)/(R_pb))=(100xx21)/(5)=420W`
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