passwella.
Menu

JAMB Physics 1984 Question 47

Question 47

Electrical Energy and Power

What is the cost of running five 50 W lamps and four 100 W lamps for 10 hours if electrical energy costs 2 kobo per kWh?

  1. A.N0.65
  2. B.N0.13
  3. C.N3.90
  4. D.N39.00
  5. E.N234.00.
Show the answer and explanation

Answer: B (N0.13)

Explanation

Power = 250 + 400 = 650 W = 0.65 kW. Energy = 0.65 × 10 = 6.5 kWh. Cost = 6.5 × 2 = 13 kobo = N0.13.