Sir,regarding Joules' law of heating somewhere in the book, it is written H=I^2 Rt and somewhere it is written H=VIt/4.2 cal. It is right that IR is substituted for V. But, Sir please note that I have a calorimeter(Joules apparatus)with a thermometer. But the thermometer will give reading in celsius. So please tell me how to change celsius in calorie or joule. It is also written on the calorimeter:1 volt,6 amp. What does this mean, I do not understand. Also please tell me why in the formula, it is written 4.2 cal. Please give full explanation about how to carry out this experiment.

Asked by Manoj | 19th Jun, 2013, 07:42: PM

Expert Answer:

Pls post one query at a time.
Amount of heat, Q = Mass x specific heat x change in temperature
H = I2Rt Joule
1 cal = 4.2 J
So, H = (I2Rt)/4.2 cal
         = (VIt)/4.2 cal

Answered by  | 19th Jun, 2013, 11:04: PM

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