Question

What is the cost to operate a 100 W lamp continuously for 1 week when the power utility rate is 20
cents/kWh?

Answer 1

Answer on Question #49195, Physics, Mechanics | Kinematics | Dynamics

What is the cost to operate a 100 W lamp continuously for 1 week when the power utility rate is 20 cents/kWh?

**Solution.**

A lamp whose power is 100 W has been operated for

$$1 \text{ week} = 7 \text{ days} \times 24 \text{ hours} = 168 \text{ hours}$$

For the light power 1000 W during 1 hour we have to pay 20 cents = 0.2$

So for lamp’s working week we pay:

P_{\text{week}} = \frac{0.2\ \$}{1000\ W \cdot 1\ h} \cdot 100\ W \cdot 168\ h = 3.36\ \

Answer: 3.36$