two identical brass balls mounted on wooden posts initially have different amounts of charge, one plus 3 uC and the other plus 15 uC. The balls are allowed to touch and then separate again. What is the final charge on each ball?
9 uC
To determine the final charge on each ball, we can apply the principle of conservation of charge. According to this principle, the total charge before and after any interaction remains the same.
Let's break down the process step by step:
Step 1: Initial Charges
The first ball has a charge of +3 uC (microcoulombs), and the second ball, mounted on a different wooden post, has a charge of +15 uC. Therefore, the total charge before they touch is +3 uC + +15 uC = +18 uC.
Step 2: Charging by Contact
When the balls touch, the charges redistribute between them until they reach equilibrium. Since the balls are identical, we can assume that each ball will acquire half of the initial total charge.
So, to find the final charge on each ball, we divide the initial total charge by 2:
Final charge on each ball = (Initial total charge) / 2
= 18 uC / 2
= 9 uC
Step 3: Final Charges
After they separate, each ball will have a final charge of +9 uC.
Therefore, the final charge on each ball is +9 uC.