Show all required solutions step by step

/in /by

The maximum vacuum created at the summit of a syphon is
A. 2.7 m of water
B. 7.4 m of water
C. 5.5 m of water
D. none

If the atmospheric pressure on the surface of an oil tank (sp. gr. 0.8) is 0.1 kg/cm2, the pressure at a depth of 2.5 m, is
A. 1 metre of water
B. 2 metres of water
C. 3 metres of water
D. 3.5 metres of water
E. 4.0 metres of water

The time required to close a valve gradually is (where L is the length of pipe and C = velocity of pressure wave)
A.
B. ≤
C. >
D. <