Question

2/ Explain the difference between gauge pressure and absolute pressure.

Answer 1

gauge pressure is the pressure difference between two points .like you measure pressure at the surface of ocean water. this will be equal to atmospheric pressure say it it 1 atm.

next you mesaure presure at some depth say 1000 m below the surface of water. there pressure will be greater. say it is 1atm+P; the difference in pressure between these two points is P. this pressure P is known as gauge pressure. and the total pressure at these is known as absolute pressure.