Q4 of 22 Page 344

Write a mathematical expression for Joule’s law of heating effect of current. Name one device which works on this principle.

We know that H = VIT

And V = IR by Ohm’s law


⇒ H = (IR)IT


⇒ H = I2RT


This is the Mathematical form of the Joule’s law of heating effect.


Iron and heater are the devices that use the Joule’s law of heating effect.


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