Question

A 75-W hall light is left on continuously. At 0.04 Ls/kWh, find the cost per week.

Answer 1

P=75W

$P=\frac{W}{t}$

$E=W=Pt$

$$E=75\times24\times7\times60\times60=45360000sec$$

$E=\frac{45360000}{1000\times3600}=12.6Kwh$

$E=0.4\times12.6Ls=0.504Ls$