If 100 J of work must be done to move electric charge equal tp 4C from a place where potential is `-10V` to another place where potential si V volt, find the value of V.

Explanation

To solve the problem, we need to find the value of potential \( V \) given that 100 J of work is done to move a charge of 4 C from a potential of -10 V to a potential of \( V \).

### Step-by-Step Solution:

1. **Understand the formula for work done in moving a charge in an electric field:**
The work done \( W \) in moving a charge \( q \) through a potential difference \( \Delta V \) is given by the formula:
\[ W = q \cdot \Delta V \]
where \( \Delta V = V_f - V_i \) (final potential minus initial potential).

2. **Identify the initial and final potentials:**
Here, the initial potential \( V_i = -10 \, V \) and the final potential is \( V \). Therefore, the potential difference \( \Delta V \) can be expressed as:
\[ \Delta V = V - (-10) = V + 10 \]

3. **Substitute the known values into the work done formula:**
We know that the work done \( W = 100 \, J \) and the charge \( q = 4 \, C \). Substituting these values into the equation gives:
\[ 100 = 4 \cdot (V + 10) \]

4. **Solve for \( V + 10 \):**
Rearranging the equation:
\[ V + 10 = \frac{100}{4} \]
\[ V + 10 = 25 \]

5. **Isolate \( V \):**
To find \( V \), subtract 10 from both sides:
\[ V = 25 - 10 \]
\[ V = 15 \, V \]

### Final Answer:
The value of \( V \) is \( 15 \, V \).