(a)[2]
State the meaning of a magnetic field.
(b)[3]
On Fig. 6.1, draw four field lines to show the magnetic field around wire P caused by the current in the wire.
(c(i))[2]
Calculate the magnetic force per unit length acting on wire Q because of wire P.
(c(ii))[1]
State the direction of the force exerted on wire Q by wire P.
(c(iii))[2]
The flux density of the magnetic field at wire P due to the current in wire Q is $1.5\,\text{mT}$. Determine the magnitude of the current in wire P. Explain your reasoning.