You could also use “blend” as well and have the blend occur along a path… But that may be too advanced? IDK
Create your initial object on one side of the knob, then copy it by mirroring it and place it on the other side.
Now create a path (half of a circle, so create a circle and delete a node: you can do this easily by using the Direct Selection Tool and selecting the little point and just pressing delete).
Now select the objects that you want to create the ticks from and select from the main menu at the top: “Object” “blend” “make” - you can adjust how many tick marks later.
Once you have the blend object done - select it and the arc - Now select “Object” “Blend” “Replace Spine”. Voila! Ticks along an arc.
If you need to edit how many ticks or how the follow the path - go to “Object” “Blend” and “Blend Options” - this will give you total control on how the objects orient themselves along the path and how many tick marks you need. This is especially great if you are trying to have this type of stuff along a squiggly line or need to adjust things later (like the ticks changing color from one side to another).
Not that the other method was wrong - it’s just editability is rather clunky if you do it that way. This way is much more user friendly - especially if you are unsure of how many tick marks you need.