An electric heater of 1200 W is operated for 3 hrs daily. What will be the electrical consumption expenses for that in the month of June ? (The electric company charges Rs 5 per unit of energy.)
Analyse
Step 1 : To get the electrical consumption expenses of the month of June, we need to know the energy consumed by the electric heater in that month in terms of units.
Step 2 : Key factors to understand :
i. To find the expenses,
`"Electrical consumption expenses "="Energy consumed (in units)"xx"charge per unit "`
ii. `"1 unit "="1 kWh"`
i.e. in order to find the energy inunit, we need to find it in terms of kWh (kilowatt hour)

Explanation

Here, power `=1200W=1.2xx10^(3)W=1.2kW`
`"Time "="3 hrs daily for 30 days …[month of June consist of 30 days]"`
`=3xx30="90 hours"`
`therefore" Energy consumed "="power"xx"time"=1.2xx90="108 kWh"`
`therefore" Electrical energy expenses "="Energy consumed "xx"charges per unit"`
`=108xx5`
`"Rs 540"`