Question

An electric current I flows through an infinitely long conductor as shown in Figure 2 (a) below. Write an expression and direction for the magnetic field at point P. 

Answer 1

`therefore` By Biot savart’s law

`vec(B) = ∫  vec (dB) = mu_0/(4pi) ∫ (I vec(dl) xx vec(r))/r^3`

The magnetic field created by a current carrying wire is radial magnetic field.