Heating Effect of Electric Current & Power

0
19
science-10th-class-cbse-notes

Heating Effect of Electric Current

Explanation → Battery or a cell is a source of electrical energy.

  • Battery or cell (Chemical reaction in it will produce potential difference at its two terminals)
  • Electron will come in motion to flow current through resistor
  • To maintain this current, the sources has to keep expending its energy.
  • Part of this energy is consumed in useful work (Like rotating of fan)
  • Rest of energy of source is converted into heat, that raises the temperature of gadget.
  • This is known as heating effect of electric current.
  • This effect is utilized in devices such as electric heater, iron etc.

The law stated that the heat produced in a resistor is

  • directly proportional to square of the current
  • directly proportional to resistance (R) for given current
  • directly proportional to time (t) for which current flow through resistor.

Application of Heating Effect of Electric Current

  • Used in electric iron, toaster, oven, heater etc.
  • It is also used in bulb to produce light.

(Filament of bulb is made of strong metal with high melting point such as tungsten. This filament can retain as much of the heat generated as possible, to become very hot and emit light)

It is also used in the fuse connected in an electric circuit. Fuse is a safety device, that protect the circuits and appliance by stopping the flow of high current. The wire of fuse is made of an alloy of metals e.g., Aluminum Copper, Iron, Lead etc. The alloy should be of low melting point and high resistivity, fuse is always connected in series circuit. When large current flows through the circuit, the temperature of fuse wire will increase. This melts the fuse wire and breaks the circuit.

“Fuses” used for domestic purposes are rated as 1A, 2A, 3A, 5A, 10Aetc. for various operation depending upon the power of appliance using.

Electric Power

In case of electricity, it is defined as the rate of change of electrical energy dissipated or consumed in an electric circuit.

P=VI

 

LEAVE A REPLY

Please enter your comment!
Please enter your name here