Effect of Electric Current And Joule’s Law of Electric Heating

Effect of Electric Current , Joule’s Law of Electric Heating And Thermal Efficiency

Effect of Electric Current

It is a matter of common expertise that a conductor, once carrying current, becomes hot once a while.  As explained earlier, an electrical current is simply a directed flow or drift of electrons through a substance.

          The moving electrons as they go through molecules of atoms of that substance, touch different electrons.  This electronic collision leads to the assembly of warmth.  This explains why passage of current is often among generation of warmth.

Joule’s Law of Electric Heating

The amount of labor needed to keep up a current of I amperes through a resistance of R ohm for t second is

                                                                   W.D. = I2 Rt  joules
                                                                            = VIt joules                                 (ä   R = V/I)
                                                                            = Wt joules                                 (ä   W = VI) 
                                                                            = V2t/R joules                             (ä  I = V/R)


This work is reborn into heat and is dissipated away. the quantity of warmth made is


Thermal Efficiency

It is outlined because the quantitative relation of the warmth really utilised to the full heat created electrically. take into account the case of the electrical kettle used for boiling water.  Out of the full heat created

(i) some goes to heat the equipment itself i.e. kettle

(ii) some is lost by radiation and convection etc. and

(iii) the remainder is employed for heating the water.  Out of those, the warmth utilised for helpful purpose .


(iii).  Hence, thermal potency of this electrical equipment is that the quantitative relation of the warmth utilised for heating the water to the full heat created.