Question

A $ 300\text{W} $ T.V. is operated every day for 6 hour. Find the electrical energy (no. of units) consumed?

Answer 1

Hint: Electric power is the rate at which the work is done or energy is transformed into an electrical circuit. Use power energy formula for this question that is given by, $ $ $ \text{power}=\dfrac{\text{Energy}}{\text{Time}}=\dfrac{\text{E}}{\text{t}} $
Here, E is energy consumption,
Unit of power is watt, time in seconds.

Complete step by step solution:
We have given, T.V. is operated at power $ =300\text{W} $
Change the units $ 1\text{KW}=1000\text{W} $
 $ 1\text{W}=\dfrac{1}{1000}\text{KW} $
Hence, power can be written as $ =\dfrac{300}{1000}=0\cdot 3\text{KW} $
Now time is given by = $ \text{6hr} $ .
Use power energy power which is given by, $ \text{power}=\dfrac{\text{Energy}}{\text{Time}} $
 $ \text{Energy}=\text{power}\times \text{time} $
Put all the values in above formula
 $ \text{Energy}=0\cdot 3\text{KW}\times \text{6hr} $
 $ =1\cdot 8\text{KWh} $
Electrical energy is given by $ =1\cdot 8 $ units
Therefore {1KWh = units}.

Note:
The commercial unit of electrical energy is a kilowatt-hour (KWh)
 $ 1\text{KWh}=1000\times 60\times 60=3\cdot 6\times {{10}^{6}}\text{J} $
The electrical energy used in factories, industries and houses are measured in KWh.
A few examples of electrical energy are:
a car battery, a chemical reaction results in the formation of an electron which possesses the energy to move in an electric current. These moving charges provide electrical energy to the circuits in the car.
Lightning, during a thunderstorm, is an example of electrical energy – what we see as lightning is nothing but electricity discharging in the atmosphere.
Electric wheels generate electrical energy.
The street lights on the road use electricity to function, even the pool requires electricity to heat the water in colder regions. The lawnmower, which is used to cut grass uses electricity to operate.