Condenser: The correct answer is option 'A' - Condenser

Explanation:

In a steam power plant, water is used for cooling purposes in the condenser. The condenser is an integral part of the power plant's steam cycle and is responsible for converting the steam back into water.

1. Function of the Condenser:
The condenser plays a crucial role in the steam power plant by condensing the exhaust steam from the turbine into water. It is a heat exchanger that transfers heat from the steam to a cooling medium, which is usually water or air.

2. Working Principle of the Condenser:
The steam enters the condenser at high pressure and temperature. Inside the condenser, the steam comes into contact with cool water or air, causing it to lose heat and condense into water. This process releases a significant amount of latent heat, which is transferred to the cooling medium.

3. Cooling Medium:
In a steam power plant, water is commonly used as the cooling medium in the condenser. The water absorbs the heat from the steam, causing it to condense and form liquid water. This cooled water is then recirculated back to the condenser for further cooling.

4. Importance of Cooling:
The cooling process is crucial in a steam power plant because it allows the steam to be condensed and reused in the boiler. This increases the overall efficiency of the power plant and reduces the amount of water required for operation.

5. Other Components:
While water is used primarily for cooling purposes in the condenser, it is also used in other components of the steam power plant. For example, water is heated in the boiler tubes to produce steam, which then passes through the turbine to generate electricity. However, the cooling function is specifically associated with the condenser.

In conclusion, water is used for cooling purposes in the condenser of a steam power plant. The condenser plays a vital role in the overall efficiency of the power plant by converting the steam back into water through the cooling process.