Q1. [1] § 12.1 MAGNETIC FIELD AND FIELD LINES § 12.2 MAGNETIC FIELD DUE TO A CURRENT-CARRYING CONDUCTOR § 12.2.2 Right-Hand Thumb Rule
A positron enters a uniform magnetic field at right angles to it as shown. The direction of force experienced by the positron will be :
- (a) to the right
- (b) to the left
- (c) into the page
- (d) out of the page
Previously asked in CBSE board exam
2023 31/2/1 Q16
Generated by claude-sonnet-4-6 · 2026-06-15 06:48 · grounding rag
Model Answer
(a) to the left
A positron is a positively charged particle. Applying Fleming's Left-Hand Rule (or the force rule F = qv × B), the direction of force on the positron is to the left.
Explanation
- A positron has positive charge (+e), unlike an electron.
- Use Fleming's Left-Hand Rule: forefinger → magnetic field direction, middle finger → direction of current/motion of positive charge, thumb → force direction.
- Since the positron is positive, its direction of motion is also the conventional current direction, so Fleming's Left-Hand Rule applies directly.
- Examiners expect you to identify the charge type and apply the correct rule to get the direction.
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