A thin wire is bent into a semicircle of radius lying in the plane of the page. A current of flows through the wire in a clockwise direction as shown. What is the direction of the magnetic field at the centre of the semicircle?
Answer
Into the page
The correct answer is Into the page — Select the option that states this direction.
Step-by-step solution
- Recall the right‑hand thumb rule: for a current element, curl the fingers in the direction of current; the thumb points in the direction of the magnetic field produced at the centre.
- For a clockwise current, the fingers of the right hand curl clockwise when the thumb points away from the observer.
- Thus the magnetic field at the centre points into the page (away from the observer).
- Select the option that states this direction.
Common mistake: Confusing clockwise with anticlockwise current, which would give the opposite (out of page) direction.
Concept tested: Magnetic field of a curved current‑carrying conductor
Published · How this solution was prepared and checked
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