MCQ
If a charged particle projected in a gravity-free room deflects:
- AThere must be an electric field.
- BThere must be a magnetic field.
- CBoth fields cannot be zero.
- DBoth fields can be non zero.
✓
Answer
- Both fields cannot be zero.
- Both fields can be non zero.
Explanation:
If a charged particle is projected in a gravity free room with some velocity, then its deflection depends on whether the particle experiences electric force or magnetic force. If electric field or magnetic field is absent in the space, then the charged particle will continue to move in the same direction with the same velocity. Thus, both electric and magnetic fields cannot be zero.
If force on the charged particle due to electric field is equal and opposite to the force due to magnetic field, then
$\text{F}=\text{qE}=\text{qvB}$
$\text{v}=\frac{\text{E}}{\text{B}}$
Thus, if anyone of the two fields is non zero, the charged particle will get deflect. Therefore, the correct option is (c) and (d).
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