1) 0.1 kWh
Explanation:
The power of the lightbulb is:
[tex]P = 100 W=0.1 kW[/tex]
The energy used by the lightbulb is equal to the product between the power (P) and the time (t):
[tex]E=Pt[/tex]
Since the bulb has been left on for t = 1 h, the total electrical energy used is
[tex]E=Pt=(0.1 kW)(1 h)=0.1 kWh[/tex]
2) $ 0.018
Explanation:
The company charges $0.18 per each kilowatt-hour. So, we can find the total cost charged for using 0.1 kWh of electricity by setting the following proportion:
$0.18 : 1 kWh = x : 0.1 kWh
And solving for x, we find
[tex]x=\frac{\$0.18 \cdot 0.1kWh}{1 kWh}=\$ 0.018[/tex]
