A particle of charge `-q` and mass m moves in a circle of radius r around an infinitely long line charge of linear charge density `+lamda`. Then, time period will be
where , `k=1/4piepsilon_0)`

Options

A. `T=2pir sqrt((m)/(2klambdaq)`
B. `T^(2)=(4pi^(2)m)/(2klambdaq)r^(3)`
C. `T^(2)=(1)/(2pir)sqrt((2klambdaq)/(m))`
D. `T=(1)/(2pir)sqrt((m)/(2klambdaq))` where `k=(1)/(4piepsilon_(0))`

Answer

A

Explanation

We have centripetal force equation
`q((2klambda)/(r))=(mv^(2))/(r) sov=sqrt((2kqlambda)/(m))`Now,
`T=(2pir)/(v)=sqrt((m)/(2klambdaq))` where `k=(1)/(4piepsilon_(0))`