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A ring of radius R carries a charge +q. ...

A ring of radius `R` carries a charge `+q`. A test charge `-q_(0)` is released on its axis at a distance `sqrt(3) R` from its centre. How much kinetic energy will be acquired by the test charge when it reaches at the centre of the ring ?

A

`(1)/(4 pi epsilon_(0)) ((qq_(0))/(R ))`

B

`(1)/(4 pi epsilon_(0)) ((qq_(0))/(2R ))`

C

`(1)/(4 pi epsilon_(0)) ((qq_(0))/(sqrt(3)R ))`

D

`(1)/(4 pi epsilon_(0)) ((qq_(0))/(3R ))`

Text Solution

Verified by Experts

The correct Answer is:
2

`K_(A) + U_(A) K_(o) + U_(o)`
`K_(A) + (-q_(0))V_(A) = K_(o) + (-q_(0)) V_(o)`
`0 + (-q_(0)) (1)/(4 pi in_(0)) (q)/(2 R) = (1)/(2) mv^(2) + (-q_(0)) .(1)/(4 pi in_(0)) (q)/(R )`
`(1)/(2) mv^(2) = (qq_(0))/(8 pi in_(0) R)`
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Knowledge Check

  • A ring of radius R is charged uniformly with a charge +Q . The potential at a point on its axis at a distance 'r' from any point on ring will be-

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