A) 80.0096 cm
B) 80.0272 cm
C) 1 cm
D) 25.2 cm
Correct Answer: A
Solution :
Using the relation \[{{l}_{1}}={{l}_{0}}(1+\alpha t)\] \[=1\times [1+1]\times {{10}^{-6}}\times ({{40}^{o}}-{{20}^{o}})]\] \[=1.00022\,\,cm\] Now, length of copper rod at\[{{40}^{o}}C\] \[l_{1}^{}=l_{0}^{}(1+\alpha t)\] \[=80\,\,[1+17\times {{10}^{-6}}({{40}^{o}}-{{20}^{o}})]\] \[=80.0272\,\,cm\] 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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