Question

How do you calculate the efficiency of energy transfer ?

Answer 1

Hint:First we need to understand the basic definition of Work done,Energy and Power and how they are related. With this understanding we can move on to learn about Efficiency which describes the amount of energy that is usefully transferred. Then using these two concepts we can arrive at an equation by which we can calculate the efficiency of energy transfer.

Complete answer:
We will begin by understanding the basic concept of Work, Energy and Power. Work is said to be done when a body moves a distance when an external force is applied.
\[W = F \times d\] , where ‘F’ is the external force while ‘d’ is the displacement.

Energy can be defined as the capacity to do work.The rate at which energy is transferred or rate of work done is defined by Power.
$P = \dfrac{W}{t}$ where ‘W’ is the work done and ‘t’ is the time.
By familiarizing these basic concepts let us now move to efficiency and how to calculate the efficiency of energy transfer.Efficiency can be defined as the proportion of energy supplied which is transferred usefully. The working condition of a device is studied by the concept of efficiency. Devices are constructed in a manner that little energy is wasted, i.e, most of the input energy should be converted as output.

We can calculate efficiency in two ways:
Decimal:
$Efficiency = \dfrac{{Amount{\text{ }}of{\text{ }}Energy{\text{ }}Transferred}}{{Total{\text{ }}Energy}}$
Percentage:
$Efficiency = \dfrac{{Amount{\text{ }}of{\text{ }}Energy{\text{ }}Transferred}}{{Total{\text{ }}Energy{\text{ }}Supplied}} \times 100$
This is how we arrive at the calculation of energy transfer.

Note:A very efficient device means the wastage will be very low while inefficient device means the wastage will be high. We can also calculate efficiency using power which will be called as efficiency of power transfer.