Define the tesla in terms of magnetic flux density.
A long solenoid has a cross-sectional area of $28\,\text{cm}^2$, as shown in Fig. 5.1. Coil C, made from 160 turns of insulated wire, is wrapped tightly around the centre of the solenoid. The magnetic flux density $B$ at the centre of the solenoid is given by $B = \mu_{0} n I$, where $I$ is the current in the solenoid, $n$ is a constant equal to $1.5 \times 10^{3}\,\text{m}^{-1}$ and $\mu_{0}$ is the permeability of free space. Calculate the magnetic flux density at the centre of the solenoid when the current is $3.5\,\text{A}$.
Calculate the flux linkage for coil C.
State Faraday’s law for electromagnetic induction.
In (b), the current in the solenoid is reversed in direction over a time of $0.80\,\text{s}$. Calculate the average e.m.f. induced in coil C.