The figure shows the cross section of two long coaxial tubes carrying equal current `I` in opposites directions. If `B_1` and `B_2` are magnetic fields at point 1 and 2 as shown in figure then

Options

A. `B_(1)!=0,B_(2)=0`
B. `B_(1)=0,B_(2)=0`
C. `B_(1)!=0,B_(2)!=0`
D. `B_(1)=0,B_(2)!=0`

Answer

A

Explanation

At distance r from centre `B=(mu_(0))/(2pi)((i_("in")))/r` (From ampere's cicuital law)
For path -1 `i_("in")1=0:,B_(1)!=0,` For path -2 `i_("in")=0:.B_(2)=0`