A) 2.4 mm
B) 2.8 mm
C) 3.2 mm
D) 3.6 mm
Correct Answer: B
Solution :
Change in length of brass rod \[\Delta {{l}_{B}}={{\alpha }_{B}}{{l}_{B}}({{T}_{2}}-{{T}_{1}})\] \[=2.5\times {{10}^{-5}}\times 500\times (200-50)\] \[=1.875\,mm\] Similarly change in length of steel rod \[\Delta {{l}_{S}}={{\alpha }_{S}}{{l}_{S}}({{T}_{2}}-{{T}_{1}})\] \[=1.25\times {{10}^{-5}}\times 500\times (200-50)\] \[=0.9375\,mm\] Therefore, change in length of the combined rod \[=\Delta {{l}_{B}}+{{l}_{S}}=1.875+0.9375\] \[=2.8125\,mm=2.8\,mm\]You need to login to perform this action.
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