The expected answers were:

(a)    Faraday’s Law of electromagnetic induction states that whenever there is a change in the magnetic flux linked with a conductor in a closed circuit, e.m.f. is induced in the conductor which causes a current to flow in it.
                                                          OR
(b)  The strength of the induced e.m.f. is directly proportional to the rate of change of magnetic flux.

(i)      Capacitance of the capacitor
                                   C  =  ∑o ∑r A/d (n-1)
                                   C  =  8.85  x  10^-12 x (6 * 6 * 0.05) / 0.0005
                                   C  =  31.86nF
                    (ii)     Charge in the capacitor
                                   Q = CV
                                       = 31.86  x  10^-9  x  400 ; Q  =  12.74μC   

This question was on electromagnetic field.  Many candidates attempted the part (a) of the question but avoided part (b).  However, the expression for calculating C for multiple plate capacitor was wrongly quoted by many candidates and consequently missed it.