A) 840 K
B) 280 K
C) 560 K
D) 380 K
Correct Answer: D
Solution :
Initially \[\eta =\frac{{{T}_{1}}-{{T}_{2}}}{{{T}_{1}}}\]Þ \[0.5=\frac{{{T}_{1}}-(273+7)}{{{T}_{1}}}\] Þ \[\frac{1}{2}=\frac{{{T}_{1}}-280}{{{T}_{1}}}\]Þ \[{{T}_{1}}=560K\] Finally \[{{\eta }_{1}}'=\frac{{{T}_{1}}'\,-{{T}_{2}}}{{{T}_{1}}^{\prime }}\]Þ\[0.7=\frac{{{T}_{1}}'\,-\,(273+7)}{{{T}_{1}}^{\prime }}\]Þ\[{{T}_{1}}'=933K\] \ increase in temperature \[=933-560=373K\approx 380K\]You need to login to perform this action.
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