In the diagram above, a 200 W bulb is lighted by a 240 V a.c mains supply. If 1kwh is sold at N40, the cost of keeping the bulb lighted for a day is?
Attached Figure / Diagram
A
N1,920.00
B
N192.00
C
N19.20
D
N1.92
Verified Correct Answer: B.
Physical Principles & Numerical Solution
Energy consumed = power x time
= 200W x 24hr = 4800wh
= 4.8 kwh
But 1 kwh cost N40
∴ 4.8kwh costs 4.8 x 40
= N192
Source: WAEC / JAMB / NECO Classroom Archive (Record #14516)