According to Joules heating effect heat produces in a resistor is
a) Directly proportional to square of current for the given resistor.
b) Directly proportional to resistance for a given current,
c) Directly proportional to the time of current flowing through the resistor.
This can be expressed as
H = I2Rt
H is heating effect, I is electric current, R is resistance and t is time
Experiment to demonstrate Joules law of heating
- Take a water heating immersion rod and connect to a socket which is connected to regulator.
- It Is important to recall that a regulator controls the amount of current flowing through a device.
- Keep the pointer of regulator on minimum and count the time taken by immersion rod to heat a certain amount of water.
- Increase the pointer of regulator to next level.
- Count the time taken by immersion rod to heat the same amount of water.
- Repeat above step for higher levels on regulator to count the time.
Observation:
- It is seen that with increased amount of electric current, less time is required o heat the same amount of water.
- This shows Joule's Law of Heating.
Application:
Electric toaster, oven, electric kettle and electric heater etc. work on the basis of leafing effect of current.
