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प्रश्न
Two similar spheres having +Q and -Q charges are kept at a certain distance. F force acts between the two. If at the middle of two spheres, another similar sphere having +Q charge is kept, then it experiences a force in magnitude and direction as ______.
पर्याय
zero having no direction.
8F towards +Q charge.
8F towards -Q charge.
4F towards +Q charge.
उत्तर
Two similar spheres having +Q and -Q charges are kept at a certain distance. F force acts between the two. If at the middle of two spheres, another similar sphere having +Q charge is kept, then it experiences a force in magnitude and direction as 8F towards -Q charge.
Explanation:
Initially, force between A and C,
F = `"kQ"^2/"r"^2`
When an identical sphere B with a charge of +Q is placed in the middle of the line connecting A and C, the net force on B is
`"F"_"net" = "F"_"A" + "F"_"C" = "kQ"^2/("r"/2)^2 + "kQ"^2/("r"/2)^2 = (8"kQ"^2)/"r"^2`
= 8F
The direction is shown in figure.
