Why is there an excess of pressure inside a liquid drop?

What is the excess pressure inside a spherical soap bubble of radius 5 cm if the surface tension of the soap film is 3.5xx10^(-2)Nm^(-1) ?

The excess of pressure inside a soap bubble is twice the excess pressure inside a second soap bubble. The volume of the first bubble in n times the volume of the second. What is the value of n?

What is the pressure inside a drop of mercury of radius 3.00 mm at room temperature? Surface tension of mercury at that temperature (20^@ C) is 4.65xx10^-1 N. m^-1 . The atmospheric pressure is 1.01xx10^5 Pa. Also give the excess pressure inside the drop.