(a) Whenever a current flows through a conductor, it gets heated up due to the resistance offered by it to the flow of electrons. This is called heating effect of current.(b) $H = I^{2} R t$ where, $H =$ Amount of heat produced, $I =$ current, $R =$ resistance of the resistor $t =$ time.(c) Electric iron and electric geyser are the two appliances based on heating effect of electric current.