A coil of wire is situated in a uniform magnetic field of flux density 
. The coil has diameter 
and consists of 350 turns of wire, as illustrated in the figure below.
The variation with time 
of is shown in the graph below.
Show that, for the time 
to time 
, the electromotive force (e.m.f.) induced in the coil is 
.
On the axes of the graph below, show the variation with time of the induced e.m.f. 
for time to time 
.
