A cylinder of radius `R_(1)` have cylinderical cavity of radius `R_(2)` as shown in the figure and have current density J (down ward). Find Magnetic field when
`rgtR_(1)` (on x-axis towards right)

Explanation

`r > R_(1)` (on x-axis towards right)

Magnetic field due to big cylinder = `B_(1)`
Magnetic field due to smaller cylinder = `B_(2)`
`B_(r)=B_(1)+B_(2)`
`=[(mu_(0)jpiR_(1)^(2))/(2pir)+{-(mu_(0)JpiR_(2)^(2))/(2pi(r-l))}]`