WAEC Physics 2021 Objective — Question 31

Question 31 of 50 from the West African Examinations Council (WAEC) Physics 2021 Objective paper, with the correct answer and a full explanation.

31. In the diagram above, a bulb is lit by drawing 2.0 A from 440 V a.c. source. Calculate the cost of keeping the bulb on for two days at $0.40 per kilowatt-hour.

A. $16.90Correct
B. $84.48
C. $1690.00
D. $8.48

Explanation

Power=VI=440×2=880W=0.88kW. Energy in 2 days (48h)=0.88×48=42.24 kWh. Cost=42.24×0.40 ≈ $16.90.

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