Question

In a siphon system employed for carrying water from a reservoir A at a higher elevation to another reservoir B at lower elevation, both being separated by a higher hill, what will be the pressure at the 'Summit'(S)?

• A. Equal to the pressure at the water surface of reservoir A
• B. Higher than the pressure at the water surface of reservoir A
• C. Equal to the pressure at the water surface of reservoir B
• D. Less than the pressure at both A and B above

Answer 1

The correct option is D Less than the pressure at both A and B above

Pressure at summit i.e. at the highest point of siphon is always negative. Therefore there is a minimum limit for pressure at the summit. It can never be allowed to go below vapour pressure. Pressure at siphon will be less than at A and B.