A cup containing 200 g of water is sitting on your dining room table. After carefully measuring it s temperature to be 20°C, you leave the room. Returning ten minutes later, you measure its temperature again and find that it is now 25°C. What can you conclude about the amount of heat added to the water? (Hint: This is a trick question.)
Step 1
The energy required to increase the temperature of the of the water is given by
Hence we can say that total 100 cal of energy was supplied to the water.
But since any kind of energy converted to the thermal energy it is not required that the energy was supplied as the form of heat.
The energy could have been supplied as work done or may be some any other form of energy which later converted to the thermal energy.
So to conclude we can say that we can’t find out the amount of heat that was supplied to the water, we can only say that the total supplied energy was 1000 cal.
