Question

A uniform magnetic field of `1*5T` is in cylindrical region of radius `10*0cm` with its direction parallel to the axis along east to west. A wire carrying current of `7*0A` in the north to south direction passes through this region. What is the magnitude and direction of the force on the wire if (a) the wire intersects the axes, (b) the wire is turned from N-S to north east-south west direction, (c) the wire in the N-S direction is lowered from the axis by a distance `6*0cm`?

Answer 1

When the wire is lowered through a distance 6.0 cm and reaches at CD then length of wire in magnetic field
`l_(2)=2x`
`x.x=4xx(10+6)=64`
x=8 cm
`therefore l_(2)=8xx12=16 cm =(16)/(100)m`
`therefore` Force on the wire
`F_(2)=BI l_(2)`
`=(1.5xx7xx16)/(100)=1.68 N` (Vertically downwards).