A uniform magnetic field `barB =B_(0)hatj` exists in a space. A particle of mass m and charge q is projected towards negative x-axis with speed v from the a point `(d,0,0)` The maximum value v for which the particle does not hit `y-z` plane is .

Options

A. `(Bqa)/(m)`
B. `(Bqa)/(2m)`
C. `(Bq)/(am)`
D. `(Bq)/(2am)`

Answer

A

Explanation

Here the paticle is projected in a direction perpendicular to the uniform magnetic field hence it will describe a circular path the particle will not hit the yz plane if the radius of the circular path is smaller than a for maximum value of v the radius of circular pth is just equal to a
or `V=(Bqa)/(m)`