The cost of electricity in the month of June for using a bulb of 500 W for 5 hours per day is: (rate of electricity is Rs 7/unit)
Rs 500
Rs 17.5
Rs 5.25
Rs 525
Answers
Given:-
→ Power of the bulb = 500 W
→ Time for which it is operated =
5 hours/day
→ Rate of electricity = Rs.7/unit
To find:-
→ The cost of electricity for the month
of June.
Solution:-
Firstly let's convert the power of the bulb from W to kW.
=> 1W = 0.001 kW
=> 500 W = 500(0.001)
=> 0.5 kW
We know that :-
Energy = Power × Time
Hence, energy consumed by the bulb in one day :-
= 0.5 × 5
= 2.5 kWh
Now, there are 30 days in the month of June. So, energy consumed by the bulb in 30 days :-
= 2.5 × 30
= 75 kWh
Therefore, cost of electricity :-
= 75 × 7
= Rs.525
Thus, cost of electricity in the month of June is Rs.525 .
Some Extra Information:-
• The unit kWh is the commercial unit of
energy used by electricity boards.
• If power is in kW (kilo-watt) and time is
in hour, then unit of energy is kWh.
• 1 kWh = 1 kW × 1h
= 1000 W × 3600s
= 3.6×10⁶ J