Explanation:

What is a Siphon?

A siphon is a tube that allows liquid to flow from a higher level to a lower level without the need for pumping. The liquid flows from the higher level to the lower level because of the pressure difference between the two levels. A siphon is used to move liquid from one container to another, or to transfer water over a ridge or hill.

What is the Summit of the Siphon?

The summit of a siphon is the highest point in the siphon, where the liquid is at its highest level. The pressure at the summit is a critical factor in the operation of a siphon.

Why is the Minimum Limit for the Pressure at the Summit of the Siphon Maintained?

The minimum limit for the pressure at the summit of the siphon is maintained for two reasons:

1. To Avoid Discontinuity: If the pressure at the summit falls below a certain minimum value, the siphon will stop working. This is because the liquid in the siphon will vaporize, creating air pockets that interrupt the flow of liquid. To avoid this, the pressure at the summit must be maintained above the minimum limit.

2. To Increase the Discharge: The pressure at the summit of the siphon also affects the rate of flow of liquid through the siphon. If the pressure is too low, the flow rate will be reduced. By maintaining the pressure at the summit above the minimum limit, the flow rate can be increased.

3. To Avoid Cavitation: Cavitation is the formation of bubbles or voids in a liquid. It occurs when the pressure in the liquid falls below the vapor pressure of the liquid. This can cause damage to the siphon and reduce its efficiency. By maintaining the pressure at the summit above the minimum limit, cavitation can be avoided.

Conclusion:

In conclusion, the minimum limit for the pressure at the summit of the siphon is maintained to avoid discontinuity, increase the discharge and avoid cavitation. By maintaining the pressure at the summit above the minimum limit, the siphon can operate efficiently and effectively.