A long cylidrical conductor of radius `R` carries a current i as shown in figure. The current desity `J` is a function of radius according to `J=br`, where `b` is a constant. Find an expression for the magnetic field `B`

a. at a distasnce `r_1ltR` and
b.at a distance `r_2gtR,` measured from the axis.

Options

A. `B_(1)=(mu_(0)br_(1)^(2))/(3),B_(2)=(mu_(0)bR^(3))/(3r_(2))`
B. `B_(1)=(mu_(0)br_(1)^(2))/(2),B_(2)=(mu_(0)bR^(3))/(3r_(2))`
C. `B_(1)=(mu_(0)br_(1)^(2))/(3),B_(2)=(mu_(0)bR^(3))/(2r_(2))`
D. `B_(1)=(mu_(0)br_(1)^(2))/(2),B_(2)=(mu_(0)bR^(3))/(2r_(2))`

Answer

A