Question

The primary winding of a transformer has 500 turns whereas its secondary has 5000 turns. The primary is connected to an ac supply of 20V, 50Hz. The secondary will have an output of:
A) $2V, 5Hz$
B) $20V, 5Hz$
C) $200V, 50Hz$
D) $20V, 500Hz$

Answer 1

Hint: Assuming ideal conditions of the Transformer we have a ratio of primary side induced voltage to the secondary side induced voltage (induced voltage is equal to supply voltage) is equal to the ratio of turns of the primary and secondary winding.
$\dfrac{{{V_1}}}{{{V_2}}} = \dfrac{{{N_1}}}{{{N_2}}}$ (Where V1 and V2 are the voltages of primary and secondary side, similarly N1 and N2 are the number of turns of primary and secondary side)
Using the above relation we will find the voltage of the secondary side.

Complete step by step solution:
Let’s discuss a few points about transformers and then we will proceed for the calculation part.
Transformer is a static device which works on the principle of electromagnetic induction. A single phase transformer has two windings primary and secondary winding .Winding having large number of turns have high voltage and the winding having less number of turns have low voltage, because voltage in a winding is directly proportional to the number of turns it has. An ideal transformer has negligible or no losses.
Now we will do the calculation for secondary side voltage:
$\dfrac{{{V_1}}}{{{V_2}}} = \dfrac{{{N_1}}}{{{N_2}}}$.....................(1)
We are being provided with primary side supply voltage, turns and turns of secondary side.
Let’s substitute the value of each in equation 1 and find the value of secondary voltage.
$
   \Rightarrow \dfrac{{20}}{{{V_2}}} = \dfrac{{500}}{{5000}} \\
   \Rightarrow {V_2} = \dfrac{{20 \times 50}}{5} \\
 $(Rearranging the terms for secondary side voltage)
$ \Rightarrow {V_2} = 200$
Secondary side voltage comes out to be 200 Volts
Frequency remains constant in the transformer;

Therefore, option (C) is correct.

Note: Transformer has two types of core named core type and shell type. Transformer core is generally made up of high permeability and low loss material like CRGO silicon steel (cold rolled grain oriented). Shell type transformers are used for low voltage applications while core type transformers are used for high voltage applications.