Question

An electric heater of resistance 10.17 Ω draws 18.99 A. If it costs 22¢/kWh, how much will it cost, in pennies, to run the heater for 2.05 h?

Answer 1

Given:

The resistance of the heater is,

`R=10.17\text{ ohm}`

The current through the heater is,

`i=18.99\text{ A}`

The cost per kWh is,

`22\text{ cents}`

To find:

The cost to run the heater for

`t=2.05\text{ h}`

Step-by-step explanation:

The energy used by the heater in this time is,

`\begin{gathered} E=i^2Rt \\ =(18.99)^2*10.17*2.05 \\ =7518.39\text{ Wh} \\ =7.52\text{ kWh} \end{gathered}`

The cost to run the heater is,

`\begin{gathered} 7.52*22 \\ =165.44\text{ cents} \end{gathered}`

Hence, the cost to run the heater is 165.44 cents or 165.44 pennies.