In a Milikan's apparatus, an oil drop of weight 2.0 x 10-15 kg acquires
two surplus electrons. When a p. d. of 620 V is applied between the pair
of horizontal metallic plates, the drop is in equilibrium. Find the
distance between the plates.
(10.0 mm)

unbalanced force

explanation:

the answer is false. this is because for ice to melt, it requires latent heat of melting. latent heat means heat energy required to change phase without any increase in temperatures. therefore, the ice will take energy from the environment to melt hence atmospheric temperatures will reduce.

the answer is the first electromagnet (a). this is because it has more coils around the ferromagnetic material. increasing the number of coils increases the surface area in which the metal interacts with the current in the coil. this enables more atoms in the metal to become aligned hence becoming more magnetized.