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A charged particle is shot with speed V...

A charged particle is shot with speed V towards another ifxed charged particle Q .It approaches Q up to a closest distnce r and then returns.If q were given a speed 2V, the closest distance of approach would be

A

r

B

2r

C

`r//2`

D

`r//4`

Text Solution

Verified by Experts

The correct Answer is:
D

At the distance of closest approach
`K_("Initial")=PE_("final")`
`1/2 mv^(2)=(Kq_(1)q_(2))/r_(0)rArr r_(0) prop 1/v^(2)`
Hence `r_(20)/r_(10)=(v_(1)/v_(2))^(2)=(v/(2v))^(2)=1/4 rArr r_(20)=r_(10)/4`
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