State Pascal's law and verify it with the help of an experiment.

Explain why

The angle of contact of mercury with glass is obtuse, while that of water with glass is acute.
 

Glycerine flows steadily through a horizontal tube of length $1.5 \mathrm{m}$ and radius $1.0 \mathrm{cm}$. If the amount of glycerine collected per second at one end is $4.0 \times {10}^{-3} \mathrm{kg} {\mathrm{s}}^{-1}$ , what is the pressure difference between the two ends of the tube? (Density of glycerine $= 1.3 \times {10}^3 \mathrm{kg} {\mathrm{m}}^{-3}$ and viscosity of glycerine $= 0.83 \mathrm{Pa} \mathrm{s}$). [You may also like to check if the assumption of laminar flow in the tube is correct]. 

What is the excess pressure inside a bubble of soap solution of radius $5.00 \mathrm{mm}$, given that the surface tension of soap solution at the temperature $(20 °\mathrm{C})$ is $2.50 \times {10}^{-2} \mathrm{N} {\mathrm{m}}^{-1}$? If an air bubble of the same dimension were formed at depth of $40.0 \mathrm{cm}$ inside a container containing the soap solution (of relative density $1.20$), what would be the pressure inside the bubble? ($1$ atmospheric pressure is $1.01 \times {10}^5 \mathrm{Pa}$).