Physics Electromagnetism MDCAT 2013
PMDC Verified Question 51 of 58
A long straight current carrying conductor has current direction from bottom to top when held vertically. What will be the direction of magnetic field lines when observed from below the conductor?
A
Clockwise
B
Vertically upward
C
Anticlockwise
D
Vertically downward
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option A: Clockwise
Concept:

The direction of magnetic field lines around a straight current-carrying conductor is determined by the Right-Hand Grip Rule. Perspective completely changes whether it appears clockwise or anticlockwise.

Formula:

$$ \text{Right-Hand Grip Rule} $$

Solution:

  • Point your right thumb in the direction of the current (bottom to top, i.e., upwards).


  • Your fingers curl around the wire in an anticlockwise direction if you were looking from the top down.


  • However, the question asks for the perspective from below the conductor looking upwards.


  • When viewed from below, an anticlockwise curl spatially translates to a clockwise observation.


Why other options are incorrect:

Option C is the perspective from above. Options B and D are impossible because the magnetic field forms closed loops around the wire, not straight lines parallel to it.

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