Physics 2011 JAMB Past Questions - Question 35: If the charges of electricity per kWh is 4 naira , what is the cost of operating an electrical appliance rated 250V, 2A for 6hours?

Correct Answer

D

Explanation

P = IV Therefore cost = IV/1000 x 6 x 4 2x 2.5 x 6 x 4/1000 = N12
To calculate the cost of operating an electrical appliance, we need to determine the total energy consumed by the appliance and then multiply it by the cost per kilowatt-hour (kWh).

First, let's calculate the energy consumed by the appliance in kilowatt-hours (kWh):

Power (P) = Voltage (V) × Current (I)
P = 250V × 2A
P = 500W

Energy (E) = Power (P) × Time (T)
E = 500W × 6 hours
E = 3000 watt-hours (Wh)

Since 1 kilowatt-hour (kWh) is equal to 1000 watt-hours (Wh), we can convert the energy to kilowatt-hours:

E = 3000 Wh ÷ 1000
E = 3 kWh

Now, we can calculate the cost of operating the appliance:

Cost = Energy (E) × Cost per kWh
Cost = 3 kWh × 4 naira/kWh
Cost = 12 naira

Therefore, the cost of operating the electrical appliance rated at 250V, 2A for 6 hours would be 12 naira.