Science (086) — AI-generated practice question

The magnetic field at the centre of the coil of 50 turns is 50 times stronger than that at the centre of the single loop.

Justification: The magnetic field at the centre of a circular loop depends directly on the current and the number of turns. In a multi-turn coil, the current in each turn flows in the same direction, so the magnetic field due to each turn adds up. Therefore, for a coil of n turns carrying the same current:

$$B_{coil} = n \times B_{single}$$

Here, $n = 50$, so $B_{coil} = 50 \times B_{single}$.

Source: Chapter 12, Section 12.2.3

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• The key principle from the textbook is: "If there is a circular coil having n turns, the field produced is n times as large as that produced by a single turn."
• Examiners award marks for: (1) stating the field is 50 times greater, (2) giving the reason (fields due to each turn add up because current direction is the same in all turns), and (3) writing the relation $B = nB_0$.
• Do not forget to justify — simply stating "50 times" without reasoning will lose marks.