Amongst iron, silver, nichrome, tungsten, copper, which metal / alloy should be used to make the (i) Heating element of electric geysers (ii) Filament of lncandescent bulbs. An electric iron has rating of 750W, 220V. Calculate: (i) Current required and (ii) Its resistance when it is in use.

Amongst iron, silver, nichrome, tungsten, copper, which metal / alloy

1.	Amongst iron, silver, nichrome, tungsten, copper, which metal / alloy should be used to make the (i) Heating element of electric geysers (ii) Filament of lncandescent bulbs. An electric iron has rating of 750W, 220V. Calculate: (i) Current required and (ii) Its resistance when it is in use.
Answer» Solution :(i) Heating element - Nichrome (ii) Filament of bulb - Tungsten P = 750 W V= 220 V (i) P =VI` :. I = (P)/(V) = (750)/(220)= 3.4 A` (ii) R = V/I `= (220V)/(3.4A)= 64.5 OMEGA`