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Last updated date: 03rd Dec 2023
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MVSAT Dec 2023

An electric iron of power \[1.5kW\] is used for \[30\] a minute, to press the clothes Calculate the electrical energy consumed in
(a) kilowatt-hour
(b) joule

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Hint: Electrical energy is a type of energy that is produced by the flow of electric charge. The ability to do work or apply force to move an object is referred to as energy. The force in the case of electrical energy is electrical attraction or repulsion between charged particles.

Complete step by step answer:
The use of power or energy of a system by making use of supply is referred to as energy consumption. Consumption is measured in gigajoules per year, kilograms of oil equivalent per year (kg/a), and Watts.
The energy consumption formula in terms of kilowatts hour is expressed as follows:
\[E=p\times \dfrac{t}{1000}\]
E =is energy in kilowatt-hours(kWh),
P= is power in Watts,
t =hours
The energy consumption formula in terms of a joule is expressed as follows:
Energy = Power x Time.
The joule is the unit of energy, the watt is the unit of power, and the second is the unit of time.
We can calculate the number of joules of electrical energy converted to sortie another form if we know the power in watts of an appliance and how many seconds it is used for.
$ p=\dfrac{w}{t} \\
 \Rightarrow w=p\times t \\
   P=1.5kW \\
  t=30~minute~=\dfrac{30}{60}=\dfrac{1}{2}hr \\
  1.5\times \dfrac{1}{2}=0.75Kwh \\
 \therefore p=0.75Kwh \\ $

$ 1kWh=3.6\times {{10}^{6}}J \\
  \Rightarrow 75kWh=0.75\times 3.6\times {{10}^{6}} \\
  =2.700\times {{10}^{6}} \\
  =2.7\times {{10}^{6}}J \\
  \Rightarrow P=2.7\times {{10}^{6}}J $

Thus, The Energy consumed in kilowatt-hour = \[0.75Kwh\]
The Energy consumed in Joule =\[2.7\times {{10}^{6}}J\].

Note: The process of producing electrical energy from other forms of energy is known as electricity generation. Michael Faraday, a British scientist, discovered the fundamental principle of electricity generation in the 1820s and early 1830s. His fundamental method is still used today: an electric current is generated by moving a loop of wire or a disc of copper between the poles of a magnet.