A very small magnet is wound with 97 layers holding 215 turns per layer. How many total turns of wire are on the coil?

• A. 20,855 turns
• B. 19,000 turns
• C. 21,000 turns
• D. 18,900 turns

Answer: (A)

When a coil has a uniform number of turns per layer, the total number of turns is found by multiplying the number of layers by the turns per layer. Here, 97 layers times 215 turns per layer gives 97 × 215 = 19,400 + 1,455 = 20,855 turns. So the coil has 20,855 turns in total. The other options aren’t equal to this product.