Question

Calculate the cost of using four $500W$ air-conditioners for eight hours each day for a $30$ day month. The unit cost of electrical energy is $Rs.1.50$ per kWh.

Answer 1

Hint: By using the formula of electrical energy, and substitute the values given in the question and we have to find the electrical energy. Also calculate the cost of electrical energy.

Complete step by step answer:
It is given that the question stated as $30$ days, Hours used per day -$8$ .Power used in watts is $500W$, the cost of electrical energy per kWh is $Rs.1.50$.

To calculate the cost of four $500W$ air –conditioners.
Electric Power: It is a measure of how much energy is used in a span of time. The electric power is defined as the rate at which work is done or energy is transformed in an electrical circuit. The unit of electrical power is Watt or joule per second. It is represented as the letter ’P’.
Electrical energy: The electrical energy is defined as the energy produced by the movement of electrons from one point to another. The movement of charged particles through the medium or along the medium constitutes the current or electricity. The unit of electrical energy is the joule or watt second.
The formula relating the energy and power is given by,
Energy ${{ = Power \times Time}}$
Where, the unit of energy is joule, the unit of power is watt, and the unit of time is second.
If the certain amount of power is dissipated for a given time, then the energy is dissipated. The energy is measured in joules.
Four $500W$ air-conditioners for eight hours each day for a $30$ day month.
$W = 4 \times 500 \times 30 \times 8$
$W = 480000W$
The unit cost of electrical energy is $Rs.1.50$ per kWh
Cost $ = 480000W \times Rs.1.50 \times {10^{ - 3}}$ per W h
$ \Rightarrow Rs.720$.
Note: One watt is the same as one joule of energy transferred per second. The difference between the power and energy is defined as energy means the capability to do work and the power is called as the energy consumed per unit time.