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.

Explanation

(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`