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A copper rod of 88cm and an aluminimum r...

A copper rod of 88cm and an aluminimum rod of unknown length have their increase in length independent of increase in temperature. The length of aluminium rod is: `(alpha_(Cu) =1.7 xx 10^(-5) K^(-1) and alpha_(Al)= 2.2 xx 10^(-5) K^(-1))`

A

68cm

B

6.8cm

C

113.9cm

D

88cm

Text Solution

Verified by Experts

The correct Answer is:
A
Here, `(Delta l)_(Cu)= (Delta l)_(Al)`
`l_(Cu) alpha_(Cu) Delta T= l_(Al) alpha_(Al) DeltaT`
`l_(Al) = (l_(Cu)) (alpha_(Cu))/(alpha_(Al))= (88 xx 1.7 xx 10^(-5))/(2.2 xx 10^(-5))= 68cm`
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