If RR time quantum is less then FCFS then more content switch per process will happen
Eg consider 10 process each having burst time 4ms and RR time quantum is 2ms and context switch time take 1ms
Total time in context switch will be 32ms in RR
Total time in context switch will be 18ms in FCFS
Now if we increase TQ by 4ms both RR and FCFS will have same context switch time