A) 8 min 20 s
B) 6 min 2 s
C) 7 min
D) 14 min
Correct Answer: A
Solution :
Heat gained by the water = (Heat supplied by the coil) ? (Heat dissipated to environment) Þ \[mc\ \Delta \theta ={{P}_{Coil}}\ t-{{P}_{Loss}}\ t\] Þ \[2\times 4.2\times {{10}^{3}}\times (77-27)=1000\,t-160\ t\] Þ \[t=\frac{4.2\times {{10}^{5}}}{840}=500\ sec\ =8\ min\ 20\ sec\]You need to login to perform this action.
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