There are two concentric conducting shells. The potential of outer shell is 10 V and that of inner shell is 15 V. If the outer shell is grounded, the potential of inner shell becomes `//` remains.

Options

A. 25 V
B. 15 V
C. 10 V
D. 5 V

Answer

To solve the problem, we need to analyze the situation involving two concentric conducting shells and how grounding the outer shell affects the potential of the inner shell.

### Step-by-Step Solution:

1. **Understanding the Initial Conditions:**
- The potential of the outer shell (V_outer) is given as 10 V.
- The potential of the inner shell (V_inner) is given as 15 V.

2. **Grounding the Outer Shell:**
- Grounding the outer shell means that its potential is set to 0 V. This is because grounding allows the shell to exchange charge with the Earth until its potential is neutralized.

3. **Effect on the Inner Shell:**
- The potential difference between the inner and outer shells before grounding is:
\[ V_{inner} - V_{outer} = 15\,V - 10\,V = 5\,V \]
- When the outer shell is grounded, its potential becomes 0 V. The potential of the inner shell will adjust according to the new potential of the outer shell.

4. **Calculating the New Potential of the Inner Shell:**
- Since the potential difference must remain the same, we can express the new potential of the inner shell (V_inner_new) as:
\[ V_{inner\_new} = V_{outer\_new} + 5\,V \]
- Substituting the new potential of the outer shell:
\[ V_{inner\_new} = 0\,V + 5\,V = 5\,V \]

5. **Conclusion:**
- After grounding the outer shell, the potential of the inner shell becomes 5 V.

### Final Answer:
The potential of the inner shell becomes 5 V.

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