Physics Electromagnetism ETEA 2022
PMDC Verified Question 30 of 58
A charged particle entered in a magnetic field anti parallel to the field, magnetic force on this particle is:
A
\( \text{BINA} \)
B
\( \text{BeV}\sin(0) \)
C
Zero
D
\( \text{Iqlv} \)
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option C: Zero
Concept:

The magnetic force requires a perpendicular velocity component relative to the magnetic field. Anti-parallel means they are exactly aligned but pointing in opposite directions.

Formula:

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

Solution:

  • Anti-parallel implies the angle between the velocity vector and magnetic field vector is \( \theta = 180^\circ \).


  • Calculate the sine of this angle: \( \sin(180^\circ) = 0 \).


  • Substitute this into the force equation: \( F = qvB(0) = 0 \).


  • The resulting force is exactly Zero.


Why other options are incorrect:

Option A is the torque on a coil. Option B uses an angle of \( 0^\circ \) which equals zero, but anti-parallel strictly means \( 180^\circ \). Option D is dimensional gibberish.

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