Explanation:

In Round Robin CPU scheduling, the time quantum is the maximum amount of time a process can run before it is preempted and moved to the back of the ready queue. When the time quantum is increased, it affects the scheduling of the processes and can have an impact on the average turnaround time.

Definition of Average Turnaround Time:
The average turnaround time is the total amount of time it takes for a process to complete, including both the waiting time and the execution time.

Effect of Increasing Time Quantum on Average Turnaround Time:
When the time quantum is increased, the following effects can be observed:

1. Decreased Context Switching: A larger time quantum means that each process is allowed to run for a longer period before being preempted. This reduces the frequency of context switching, which is the overhead involved in switching between processes. As a result, the average turnaround time may decrease.

2. Increased Waiting Time: With a larger time quantum, each process is allowed to run for a longer period. This can lead to an increase in the waiting time for processes that are waiting in the ready queue. As a result, the average turnaround time may increase.

3. Variation in Burst Times: Processes typically have varying burst times, which is the amount of time they require to complete their execution. When the time quantum is increased, processes with shorter burst times may be able to complete their execution within the time quantum, while processes with longer burst times may be preempted multiple times. This can lead to irregular variations in the average turnaround time.

Conclusion:
In conclusion, as the time quantum is increased in Round Robin CPU scheduling, the average turnaround time can vary irregularly. The effects of increasing the time quantum include decreased context switching, increased waiting time, and variations in burst times, which can impact the overall average turnaround time of the processes.