Physics Electromagnetism SZABMU 2022
PMDC Verified Question 26 of 58
The force exerted on charge particle will be maximum when it enters the magnetic field at:
A
\( 60^\circ \)
B
\( 90^\circ \)
C
\( 0^\circ \)
D
\( 45^\circ \)
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option B: \( 90^\circ \)
Concept:

The force on a charge particle in a magnetic field is governed by the vector cross product, mathematically relying on the sine of the incident angle.

Formula:

$$ F = qvB \sin(\theta) $$

Solution:

  • To maximize the force \( F \), the trigonometric function \( \sin(\theta) \) must be at its maximum positive value.


  • The maximum value of the sine function is \( 1 \).


  • This occurs exactly when the angle \( \theta = 90^\circ \) (perpendicular entry).


  • Thus, entering the field perpendicularly results in maximum deflection force.


Why other options are incorrect:

Option C results in \( 0 \) force. Options A and D result in intermediate fractional forces (\( \frac{\sqrt{3}}{2} \) and \( \frac{\sqrt{2}}{2} \) of the maximum, respectively).

Quality & Fidelity Assurance: Every question on BeambePrep is rigorously curated against the official PMDC syllabus with zero filler, zero out-of-syllabus content, and zero typos. When an authentic past paper originally contained a historical mistake or ambiguity from the examining board (such as UHS or NUMS), BeambePrep faithfully reflects the original paper while detailing the nuance and scientific consensus in the autopsy above.

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