Two identical charges are placed a fixed distance apart. The point where the resultant field is zero lies
Correct answer: A. midway between them
- A. midway between them
- B. at one of the charges
- C. outside the pair, beyond the smaller charge
- D. nowhere, since the field is never zero
Explanation
For like charges of equal magnitude the two fields are equal and opposite at the midpoint, so they cancel there. If the charges were unlike, no point between them could give cancellation because both fields would point the same way, and the null point would lie outside the pair on the side of the smaller charge. Working out which case applies is the first step in any such question.
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About Electric Field Intensity
Electric field intensity is the force acting per unit positive test charge, with direction set by the force on that charge. Work includes fields of point charges, vector superposition, field lines and the relation between field and electric potential. Field intensity must be distinguished from electric force and potential.
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