JEE MainPhysicsMagneticsMCQ+4 / −1
An electron is moving along the positive -axis. If the uniform magnetic field is applied parallel to the negative z-axis, then A. The electron will experience magnetic force along positive y-axis B. The electron will experience magnetic force along negative y-axis C. The electron will not experience any force in magnetic field D. The electron will continue to move along the positive -axis E. The electron will move along circular path in magnetic field Choose the correct answer from the options given below:
- AA and E only
- BB and D only
- CB and E only
- DC and D only
View written solutionFree
Correct answer: C
-
Given
- Electron velocity is along positive -axis:
- Magnetic field is along negative -axis:
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Magnetic force formula For an electron, charge is negative:
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Find
Using cross-product relations:
Therefore,
So for a positive charge, force would be along positive -axis.
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Since the particle is an electron The electron has negative charge, so the force direction is opposite to : Hence force is along negative -axis.
Therefore, statement B is correct and A is false.
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Nature of motion The velocity is perpendicular to the magnetic field: In a uniform magnetic field, when , the charged particle moves in a circular path.
Therefore, statement E is correct.
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Check remaining statements
- C: "The electron will not experience any force" → false
- D: "The electron will continue to move along positive -axis" → false, because magnetic force changes its direction continuously.
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Correct combination Correct statements are B and E only.
From the given options, this corresponds to:
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