Question

A long straight wire AB carries a current of 4 A. A proton P travels at `4xx10^(6) ms^(-1)` parallel to the wire 0.2 m from it and in a direction opposite to the current as shown in the figure. Calculate the force which the magnetic field due to the current carrying wire exerts on the proton. Also specify its direction.

Answer 1

Magnetic field field at point P
`B=(mu_(0))/(4pi)(2I)/(r)`
Force experienced by proton
`F=qvB`
`F=qv(mu_(0))/(4pi)(2I)/(r)`
`F=(16xx10^(-19)xx4xx10^(6)xx2xx4)/(0.2)`
`F=25.6xx10^(-19)N`
Force will be repulsive i.e. force on proton will be away from the wire AB in the plane of paper.