Question

a windmill captures 700w of wind power for 10h. the kinetic energy is converted to electric energy and stored in a battery, before being used by a 60w light bulb. during the process 65% of the energy is lost. wind energy captured: 70 wh loss: 45.5 wh energy delivered to light bulb: 24.5 wh how long could the light bulb be used? hours

Explanation:

Step1: Recall power - energy formula

Power $P=\frac{E}{t}$, where $P$ is power, $E$ is energy and $t$ is time. We want to find $t$, and we know $P = 60W$ and $E=24.5Wh$.

Step2: Rearrange the formula to solve for $t$

$t=\frac{E}{P}$.

Step3: Substitute the values

$t=\frac{24.5Wh}{60W}=\frac{24.5}{60}h\approx0.4083h$.

Answer:

$0.4083$