Question

A bulb of 40 W is used for 12.5 h each day for 30 days. Calculate the electrical energy consumed.

• A. 15 kWh
• B. 7.5 kWh
• C. 1.5 kWh
• D. 0.15 kWh

Answer 1

The correct option is A 15 kWh

The power of the electric bulb is 40 W which is equal to 0.04 kW. The energy consumed per day is given as total running time multiplied by the power.
Therefore, the energy consumed per day is , $EnergyconsumedQ=timetakent\times powerconsumed=0.04kW\times 12.5hr=0.5kWh$.
For 30 days, the energy consumed is given as $0.5kWh\times 30=15kWh$.
Hence, the total energy consumed for 30 days is 15 kWh.