A radio set operates at `6 V DC`. A transformer with 18 turns in the secondary coil is used to step down the input `220 V AC emf to 6 V AC emf`. This `AC emf` is then rectified by another circuit to give `6 V DC` which is fed to the radio. Find the number of turns in the primary.

Explanation

To find the number of turns in the primary coil of the transformer, we can use the transformer equation which relates the voltages and the number of turns in the primary and secondary coils. The formula is given by:

\[ \frac{E_2}{E_1} = \frac{N_2}{N_1} \]

Where:
- \(E_1\) = Voltage in the primary coil (input voltage)
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