Question

An electric iron draws a current of 4 Ampere on a 240 V supply
1.what is its power
2.what is its resistance
3.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

Hey,

(i) Potential difference=240 Volt
Current=4 Amphere
Power=potential difference*current
=240*4=960Watt

(ii) Resistance=(Potential difference)^2/Power
=(240)^2/960
=60 ohm
(iii) Energy used=Power(in watt)*time(in hours)/1000=960*10/1000=96kWh

cost of using iron=energy*cost per kWh
=96*3.40=₹326.40


#hope it helps