A transformer is connected to a \(240 V\)-supply. The primary coil has 40 turns, and the secondary is found to be \(960 V\). What is the ratio of the number of turns of the primary coil to the number of turns of the secondary coil?
A. \(1: 4\) B. \(4: 1\) C. \(1: 6\) D. \(6: 1\)
Correct Answer: A
Explanation
\(N_{p}=40\) turns \(V_{s}=960 V , V_{P}=240 V\) Required: \(\frac{N_{P}}{N_{s}}=\) ? from the transform- ation ratio of an ideal transformer, we use \(\frac{V_{s}}{V_{p}}=\frac{N_{s}}{N_{P}}=\frac{I_{P}}{I_{S}}\) \begin{aligned} \frac{V_{s}}{V_{p}} &=\frac{N_{s}}{N_{p}}, \frac{N_{P}}{N_{s}}=\frac{V_{P}}{V_{s}} \\ &=\frac{240}{960}=\frac{1}{4}=1: 4 \end{aligned}
