Question

An electric iron draws a current of 15 A from a 220 V supply. What is the cost of using iron for 30 min everyday for 15 days if the cost of unit (1 unit $=$ 1 k W hr) is 2 rupees?

• A. Rs. 49.5
• B. Rs. 60
• C. Rs. 40
• D. Rs. 10

Answer 1

Answer: (A)

Rs. 49.5

$I=15A,V=220V,t=30min$
$Energy=P\times t=VIt$
$=220\times 15\times \frac{30}{60}\times 15$
$=3300\times \frac{1}{2}\times 15Whr$
$=3.3\times kW\times 7.5hr$
$=24.75kWhr$
$Cost=24.75\times 2=Rs.49.50$