Question

(i) What is Joule’s law of heating? Give its formula.

(ii) An electric iron consumes energy at a rate of 840 W when heating is at the maximum rate & 360W

when the heating is at the minimum. The voltage is 220 V. What are the current and the resistance

in each case?​

Answer 1

Answer:

(I) A quantitative form of Joule's law is that the heat evolved per second, or the electric power loss, P, equals the current I squared times the resistance R, or P = I2R. The power P has units of watts, or joules per second, when the current is expressed in amperes and the resistance in ohms.

(II)An electric iron consumes energy at a rate of 840w when heating is at the max rate and 360w when heating is at minimum.

Explanation:

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