A) 80.0096 cm
B) 80.0272 cm
C) 1 cm
D) 25.2 cm
Correct Answer: A
Solution :
Using the relation \[{{l}_{t}}={{l}_{0}}(1+\alpha t)\] \[=1\times [1+11\times {{10}^{6}}\times (40{}^\circ -20{}^\circ )]\] \[=1.00022\text{ }cm\] Now, length of copper rod at \[40{}^\circ C\] \[l{{}_{t}}=l{{}_{0}}(1+\alpha t)\] \[=80[1+17\times {{10}^{6}}(40{}^\circ -20{}^\circ )]\] \[=80.0272\text{ }cm\] Now, number of cms observed on the scale \[=\frac{80.0272}{1.00022}=80.0096\]You need to login to perform this action.
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