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Science — CBSE Class 10 board question

Q1. [1]
Assertion (A) : The strength of the magnetic field produced at the centre of a current carrying circular coil increases on increasing the number of turns in it. Reason (R) : The current in each circular turn has the same direction and the magnetic field due to each turn then just adds up.
  1. (a) Both (A) and (R) are true and (R) is the correct explanation of (A).
  2. (b) Both (A) and (R) are true, but (R) is not the correct explanation of (A).
  3. (c) (A) is true, but (R) is false.
  4. (d) (A) is false, but (R) is true.
Previously asked in CBSE board exam
2023 31/1/1 Q20
Generated by claude-sonnet-4-6 · 2026-06-15 06:51 · grounding rag
Model Answer

(a) Both (A) and (R) are true and (R) is the correct explanation of (A).

The field is n times larger with n turns because current in each turn flows in the same direction, so magnetic fields due to each turn add up.

Explanation

The source passage (12.2.3) directly states: "if there is a circular coil having n turns, the field produced is n times as large… because the current in each circular turn has the same direction, and the field due to each turn then just adds up." This makes (R) the precise reason for (A), so option (a) is correct.

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