Question

A power transmission line feeds input at $2200Volts$ to a step-down transformer with its primary winding having $3000$ turns.find the number of turns in the secondary coil to get the power output at $220Volts$.

Answer 1

Transformers are electrical devices consisting of two or more coils of wire used to transfer electrical energy by means of a changing magnetic field
There are 2 types of transformers
Step up and step down transformers.
Step down transformer reduces down the voltage through its secondary winding at the output junction
This question has to be solved from turns ratio. A transformer always has a constant which is called turns ratio which is also equal to the ratio of voltage at primary and secondary side.

Complete step by step answer:
The turns ratio for an ideal transformer is defined as ratio of number of turns in primary as well as secondary winding. It is a constant

Transformers are all about “ratios”. The ratio of the primary to the secondary, the ratio of the input to the output, and the turns ratio of any given transformer will be the same as its voltage ratio.

$\dfrac{{{N}_{P}}}{{{N}_{S}}}=\dfrac{{{V}_{P}}}{{{V}_{S}}}=n=cons\tan t$

Now according to question we need to find ${{N}_{S}}$
${{V}_{P}}=2200Volts$
${{N}_{P}}=3000$
${{V}_{s}}=220Volts$
Putting the values
$\Rightarrow \dfrac{3000}{{{N}_{S}}}=\dfrac{2200}{220}$
${{N}_{s}}=\dfrac{3000}{10}turns$
$\Rightarrow {{N}_{S}}=300\,Turns$

So the secondary coil should have 300 turns.

Note:
Transformers work on the principle of conservation of power.
It does not generate voltage in the step-up transformer rather increase or decrease voltage at the cost of current.
When output voltage increases current decreases and vice-versa to keep the power constant.
A transformer operates on the principles of “electromagnetic induction”, in the form of mutual Induction.
Mutual induction is the process by which a coil of wire magnetically induces a voltage into another coil located in close proximity to it.