Answer 1

A rate of emission of electrons from a metal surface depends on
(1) Nature of the metal surface: Lower the work function of the metal, greater is the rate of emission of electrons from its surface.
(2) The temperature of the surface: Higher the temperature of the surface, greater is the rate of emission of electrons from the surface.
(3) Surface area of the metal: Larger the surface area of the metal emitting electrons, greater is the rate of emission of electrons.

Answer 2

(i) The material of the surface,
(ii) The temperature of the surface,
(iii) The surface area of the surface.