Page 42 - CHAPTER-1 (Electricity)

CHAPTER 1

ELECTRICITY

Example 16:

An electric iron is consuming energy at a rate of 880 W, when heating

is at the maximum rate and 340 W, when the heating is at the

minimum rate. The voltage is 220 V. What are the current and the

resistance is each case?

Solution:

Power, = , Current = /

(i) When heating is at the maximum rate,

880
I= =4A
220

Resistance of the electric iron,

V 220
R= = =55Ω
I 4

(ii) When heating is at the minimum rate,

340
I= =1.54A
220

Resistance of the electric iron,

V 220
R= = =142.85Ω
I 1.54

40