Question

Calculate the electrical energy consumed by a 1200 W toaster in 30 minutes.what will be the cost of using the same for 1 month if 1 unit of electricity cost ₹4

Answer 1

$energy \: consumed = (1200 \times 15) \div 1000 \\ \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: = 1.2 \times 15 \\ \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: = 18units \\ cost = 4 \times 18 = rs72$

Answer 2

i) P = 1200 W  t =30 min = 0.5 h  

Electrical energy (E) =P x t = 1200 x 0.5

                                           = 600W/h = 0.6 kWh.

(ii) Energy consumed is 30 days

= 0.6 x 30 = 18 kWh  

Cost of using 18 units = 7 4 x 18 = 72