Find the electrical energy expended by an electrical lamp labelled 100W in 8 seconds
one watt = 1 J/s
so,
100J/s * 8s = ____ J
or, since electrical energy is often measured in watt-hours,
100W * 8s = 800 W-s = 2/9 W-hr
To find the electrical energy expended by the lamp, we can use the formula:
Energy = Power x Time
Given:
Power (P) = 100W
Time (t) = 8 seconds
Substitute these values into the formula:
Energy = 100W x 8 seconds
Now, multiply the power (100W) by the time (8 seconds):
Energy = 800 Joules
Therefore, the electrical energy expended by the lamp labelled 100W in 8 seconds is 800 Joules.
To calculate the electrical energy expended by the lamp, we can use the formula:
Energy (E) = Power (P) × Time (t)
Given:
Power (P) = 100W
Time (t) = 8 seconds
Substituting the given values into the formula, we have:
E = 100W × 8 seconds
To further simplify the calculation, we'll convert 100W to kilowatts (kW) since the standard unit for energy is kilowatt-hours (kWh).
1 kilowatt (kW) = 1000 watts (W)
Therefore, 100W = 100/1000 = 0.1 kilowatts (kW)
Now, we can calculate the energy expended:
E = 0.1 kW × 8 seconds
E = 0.8 kilowatt-seconds (kWs)
However, kilowatt-seconds (kWs) is not the standard unit for energy; kilowatt-hours (kWh) is. To convert the energy from kilowatt-seconds (kWs) to kilowatt-hours (kWh), we need to divide the value by 3600 (the number of seconds in an hour).
E = 0.8 kWs ÷ 3600
E ≈ 0.00022 kilowatt-hours (kWh)
Therefore, the electrical energy expended by the 100W lamp in 8 seconds is approximately 0.00022 kilowatt-hours (kWh).