Step 1: Understanding the Concept:
Initial charge: \(Q_0 = CV = 10\times10^{-6} \times 50 = 500\,\mu C\). Extra charge given = \(200\,\mu C\).
Step 2: Detailed Explanation:
Total charge on system: \(= 500 + 200 = 700\,\mu C\). For an isolated capacitor, effective charge producing potential difference: \(Q = \frac{700 + 500}{2} = 600\,\mu C\). \(V = \frac{Q}{C} = \frac{600}{10} = 60\,V\).
Step 3: Final Answer:
\(\boxed{60\ \text{V}}\)