A metal kettle rated 1100 W, 220 V has its metallic body connected to earth through a…
PHYSICS · Multi-part · CBSE · Physics · Magnetic Effects of Electric Current · Magnetic Effects of Electric Current
Problem
A metal kettle rated 1100 W, 220 V has its metallic body connected to earth through a wire of resistance 1Ω. The live conductor inside the kettle accidentally touches the body while the kettle is switched on. A person whose body resistance to ground is 1×105Ω touches the kettle at the same instant.
(i) Calculate the current that flows through the earth wire immediately after the fault.
(ii) Determine the approximate potential of the kettle’s body with respect to ground just before the fuse melts, assuming the supply voltage remains 220 V.
(iii) If the earth wire were absent, calculate the current that would flow through the person’s body under the same circumstances.
(iv) Comment on the relative safety of the two situations on the basis of your calculations.