Answer:
Tension in the string will increase
Step-by-step explanation:
As we know that tension in the string at any angle with the vertical is given as

now we have

also we know that
angular speed of the stone is directly depending on the time period of the motion
so it is given as

since the frequency of the revolution is increased from n = 1 rev/s to 2 rev/s
so the angular speed would be doubled
So here we can say that
tension in the string will increase when we will increase the frequency of revolution.