A transformer has a 1:6 turns ratio and a secondary coil load resistance of 470 Ω. The load resistance as seen by the source is

Answer: Option D

Here's an explanation to help you understand how to solve this transformer question:

The question involves the concept of the turns ratio of a transformer and how it relates to the impedance transformation.

Turns Ratio (N1:N2): In this problem, the turns ratio is given as 1:6. This means for every 1 turn in the primary coil, there are 6 turns in the secondary coil. We can represent this as N1/N2 = 1/6.

Impedance Transformation: A transformer changes the apparent impedance (resistance in this case) seen by the source (primary side). The relationship is:

Z1 = (N1/N2)^2 * Z2

Where:
Z1 is the impedance seen by the source (primary side).
Z2 is the impedance of the load connected to the secondary side.
N1/N2 is the turns ratio.

In our problem:
N1/N2 = 1/6
Z2 = 470 Ω

Now, let's calculate Z1:
Z1 = (1/6)^2 * 470
Z1 = (1/36) * 470
Z1 ≈ 13.05 Ω

Therefore, the load resistance as seen by the source is approximately 13 Ω.

So the correct answer is Option D: 13 Ω