1.      What is Joule’s heating effect? How can it be demonstrated experimentally? List its four applications in daily life.

Soln:

According to Joules heating effect heat produces in a resistor is

1. Directly proportional to square of current for the given
2. Directly proportional to resistance for a given current,
3. Directly proportional to the time of current flowing through the 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 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 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.