question_answer

Two litres of water of at initial temperature of \[{{27}^{o}}C\] is heated by a heater of power 1KW in a kettle. If the lid of the kettle is open, then heat energy is lost at a constant rate of\[160J/s\]. The time in which the temperature will rise from \[{{27}^{o}}C\] to \[77{}^\circ C\] is (specific heat of water\[=4.2\text{ }KJ/kg\]):

A)  \[5\text{ }min\text{ }20\text{ }s\]                  

B)  \[8\text{ }min\text{ }20\text{ }s\]

C)  \[10\text{ }min\text{ }40\text{ }s\]                

D)  \[12\text{ }min\text{ }50\text{ }s\]