An electric lamp is marked 60 W , 230 V . The cost of a 1 kWh of energy is Rs . 1.25. The cost of using this lamp 8 hrs a day for 30 day is

Options

A. Rs 30
B. Rs 16
C. Rs 18
D. Rs 20

Answer

C

Explanation

Heat energy
`H = (V^(2)/R)t = Pt = 60 xx 8 xx 30 = 14400 Wh = 14.4 kWh`
Cost `=14.4 xx 1.25 = Rs 18`