Question

An electric iron is used on a 240V supply and draws a current of 4 Ampere?
(a) What is its power?
(b) What is its resistance?
(c) What is the cost of using the iron for the month of January 10 hours a day if 1 kwh costs Rs.3.40?

Answer 1

a) Power = potential difference * current= 240 * 4 = 960 W
b) Resistance = potential difference / current = 240/ 4 = 60 ohms
c) energy consumed in one day = work done = Power * time = 960 * 10 = 9600 Watt-hour = 9.6 kWh
Cost for January or 31 days = cost for 1 kWh * energy consumed in a day * number of days
= 3.40 * 9.6 * 31 = Rs 1011.84

Answer 2

Given
Potential difference (v) =240V
Current (I)=4A

a) Power(P)=VI=240×4=960
b) Resistance (R)=V/I=240/4=60ohm
c) 3246