A very large swimming pool filled with water of temperture equal to `20^(@)`C is heated by a resistor with a heating power of 500 W for 20 minutes. Assuming the water in the pool is not in any contact with anything besides the resistor, determine the following quanties.
Is the process reversible ? (Y/N)

Answer

To determine whether the process of heating the swimming pool water is reversible or not, we need to analyze the nature of the process involved.

### Step-by-Step Solution:

1. **Understanding the Process**:
- The swimming pool is initially at a temperature of 20°C.
- A resistor with a heating power of 500 W is used to heat the water for 20 minutes.

2. **Calculating the Total Energy Supplied**:
- Power (P) = 500 W (watts)
- Time (t) = 20 minutes = 20 × 60 seconds = 1200 seconds
- Energy (Q) supplied = Power × Time = 500 W × 1200 s = 600,000 J (joules)

3. **Nature of the Process**:
- The heating of water by a resistor involves the transfer of heat from the resistor to the water.
- The water is not in contact with any other system (it is isolated except for the resistor).
- The process involves a temperature change in the water, and the heat is added continuously.

4. **Reversibility of the Process**:
- A process is considered reversible if it can be reversed without leaving any change in the system and surroundings.
- In this case, once the water is heated, if we were to stop the heating, the water would not return to its original temperature without some form of heat loss to the environment.
- Since the water is being heated and there is no mechanism to return the system to its initial state without external work or heat exchange, the process cannot be reversed.

5. **Conclusion**:
- Therefore, the process of heating the swimming pool water by the resistor is **not reversible**.

### Final Answer:
**Is the process reversible?** **No**