Question

A transformer with 1000 turns on its primary coil has an RMS potential difference across this coil of 240V. A voltmeter is connected across the secondary coil and measures 12V. How many turns are on the secondary coil?

Answer 1

Given that the number of turns in the primary coil is

$n_p=\text{ 1000}$

The voltage in the primary coil is

$V_p=240\text{ V}$

The voltage in the secondary coil is

$V_s=\text{ 12 V}$

We have to find the number of turns in the secondary coil.

Let the number of turns in the secondary coil be denoted by

$n_s$

The formula to calculate the number of turns in the secondary coil is

$\begin{gathered} \frac{V_p}{V_s}=\frac{n_p}{n_s} \\ n_s=\frac{V_s}{V_p}\times n_p \end{gathered}$

Substituting the values, the number of turns in the secondary coil will be

$\begin{gathered} n_s=\frac{12}{240}\times1000 \\ =50 \end{gathered}$

Thus, the number of turns in the secondary coil is 50