Question

An electric refrigerator rated 1 kW operates 6 hour/day. The
cost of energy to operate it for 30 days at 3.00 per unit is​

Answer 1

Answer

Energy - power ×time

1 kW×6 =6kWh

energy used in 30 days =6×30= 180 kWh

cost of electricity = electrical energy in kWh ×cost per kWh

180×3=₹540

Answer 2

The operating cost is Rs. 540

Given : An electric refrigerator rated 1 kW operates 6 hour/day.

To find : The operating cost at Rs. 3.00 per unit.

Solution :

We can simply solve this numerical problem by using the following process. (our goal is to calculate the operating cost)

Here, we have to use the following mathematical formula.

Energy = Power × Time

For 1 day :

• Power = 1 kW
• Time = 6 hours

So, for 1 day the energy consumption = 1 × 6 = 6 kWh

For 30 days :

Energy consumption = Energy consumption of 1 day × 30 = 6 × 30 = 180 kWh

Now, we know that :

1 kWh = 1 unit

So,

180 kWh = (1 × 180) units = 180 units

Now,

Operating cost for 1 unit = Rs. 3

So,

Operating cost for 180 units = Rs. (3×180) = Rs. 540

(This will be considered as the final result.)

Hence, the operating cost is Rs. 540