A hydraulic ram (hydram) is a water-lifting device that uses the momentum of a large flow available at low head to deliver a small flow at a high head. Identify the most accurate description of its function among the choices.

Introduction:
The hydraulic ram is a century-old, robust pump that requires no external power. It exploits water hammer from an intermittent waste flow to raise a fraction of that water to a much higher elevation, serving remote communities and hilly terrains.

Given Data / Assumptions:

• Continuous supply of water at low head (drive head).
• Hydram with waste (impulse) valve and delivery (check) valve.
• Short, rigid drive pipe for effective pressure rise.

Concept / Approach:
During each cycle, the waste valve shuts suddenly, generating a pressure surge (water hammer) in the drive pipe. This surge opens the delivery valve momentarily, pushing a small parcel of water into the air chamber and up the delivery pipe to a higher head. Over many cycles, a modest but continuous high-head discharge is obtained, sacrificing a larger low-head flow to waste.

Step-by-Step Solution:
1) Water flows through the waste valve until velocity builds.2) Waste valve slams shut → pressure rise.3) Delivery valve opens → water enters air chamber and delivery line.4) Pressures equalize; cycle repeats, achieving net elevation gain.

Verification / Alternative check:
Energy balance shows output head greatly exceeds drive head, with efficiency typically 50–70% for the lifted fraction.

Why Other Options Are Wrong:
Store energy: an air chamber smooths flow but storage is not the primary function.

Increase pressure of water: true locally but incomplete and nonspecific.

Lift from deep wells: hydram needs a flowing source, not deep suction.

Convert alternating to steady flow: incidental smoothing via air chamber only.

Common Pitfalls:
Underestimating the need for proper drive pipe design; confusing hydram with conventional reciprocating pumps.

Final Answer:
to lift small quantity of water to a greater height when a large quantity of water is available at a smaller height