Draw the pattern of the magnetic field produced around a vertical current carrying straight conductor passing through a horizontal cardboard. Mark the direction of current and the magnetic field lines. Name and state the rule which is used to determine the direction of magnetic field associated with a current carrying conductor.
Generated by claude-sonnet-4-6 · 2026-06-15 06:49 · grounding rag
Model Answer
Diagram:
```
↑ Current (upward)
|
···←··|··←···
↓ | ↑
···→··|··→···
|
(Concentric circles around wire, anticlockwise when current flows upward)
```
The magnetic field appears as concentric circles centred on the wire, lying in the horizontal plane of the cardboard. When current flows upward, field lines are anticlockwise (viewed from above).
Name of Rule: Right-Hand Thumb Rule
Statement: Imagine holding a current-carrying straight conductor in your right hand such that the thumb points in the direction of current. Then the fingers wrap around the conductor in the direction of the magnetic field lines.
Source: Chapter 12, Section 12.2.1 and 12.2.2
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Explanation
- 1 mark for the diagram — show the wire passing through the cardboard, concentric circles around it, arrows on circles showing field direction, and arrow on wire showing current direction.
- 1 mark for naming the rule (Right-Hand Thumb Rule).
- 1 mark for the correct statement of the rule — both parts (thumb → current, fingers → field) must be mentioned.
- Examiners expect the rule to be stated in the exact textbook language. Avoid describing the left-hand rule by mistake.