A constant current is maintained in a long straight vertical wire. A Hall probe is positioned a distance 
from the centre of the wire, as shown in the figure below.
The Hall probe is now replaced with a small coil of wire connected to a sensitive voltmeter. The coil is arranged so that its plane is normal to the magnetic field of the wire.
State Faraday’s law of electromagnetic induction and hence explain why the voltmeter indicates a zero reading.
State three different ways in which an e.m.f. may be induced in the coil.
