A calorimeter of negligible heat capacity holds 400 g of a liquid and a heater. At 6 V and 3 A the liquid warms from 20°C to 26°C in 4 min. Without the liquid, the calorimeter alone holds steady at 30

Question

A calorimeter of negligible heat capacity holds 400 g of a liquid and a heater. At 6 V and 3 A the liquid warms from 20°C to 26°C in 4 min. Without the liquid, the calorimeter alone holds steady at 30°C when the heater runs at 5 V and 2 A. Surroundings are at 20°C and loss is proportional to the excess temperature. Find the specific heat of the liquid in J/(kg K).

TestHub · Accepted Answer

Steady state: 10 W is lost at 10°C excess, so loss = 1 W per °C. Run 1: heater power 18 W; mean temperature 23°C, excess 3°C, loss = 3 W; net power = 15 W . Heat stored in 240 s = 3600 J . c = 0.4 ( 6 ) 3600 ​ = 1500 J/(kg K).

Physics - Heat & Thermo Question with Solution | TestHub

Doubts & Discussion