In a parallel plate capacitor, how is the capacity affected, when without changing the charge:
(i) the distance between the plates is doubled;
(ii) the area of the plate is halved.

Capacitance is given by 
where,
'A' is the area of plates and 'd' is the distance between plates.

(i) $\mathrm{As}, \mathrm{C}\propto \frac{1}{\mathrm{d}};$ when distance between the plates is doubled, capacity is halved.
(ii) Since, C ∝ A; when area of plates is halved, capacity is also halved.