Question

The diagram below shows the top view of the Wire A shown by a cross (X) carrying current into the plane of the paper. Which of the compasses is correctly aligned with the magnetic field, produced by the current carrying wire?

• A. Only 1 is aligned
• B. Only 2 is aligned
• C. Both 1 and 2 are aligned
• D. Both 1 and 2 are not aligned

Hint:

Remember the conventions for current direction: \(\otimes\) (cross) is current going INto the page (like the tail of an arrow), and \(\odot\) (dot) is current coming OUt of the page (like the tip of an arrow).

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
The Right-Hand Thumb Rule determines the direction of the magnetic field around a straight conductor.
Step 2: Key Formula or Approach:
Thumb = Direction of current. Fingers = Direction of magnetic field lines.
Step 3: Detailed Explanation:
The cross (X) indicates that the current is flowing into the paper.
Using the Right-Hand Thumb Rule, point your thumb into the page. Your fingers curl in a clockwise direction.
The magnetic field lines are circles centered on the wire.
At position 1 (Top), the clockwise tangent points to the right. Compass 1 shows this direction. (Aligned).
At position 2 (Right), the clockwise tangent points downwards. Compass 2 shows an upward direction. (Not aligned).
Step 4: Final Answer:
Only compass 1 is correctly aligned.