Write the spherical mirror's formula and explain the meaning of each symbol used in it.

Answer

### Step-by-Step Solution:

1. **Write the Spherical Mirror Formula**:
The formula for a spherical mirror is given by:
\[ \frac{1}{V} + \frac{1}{U} = \frac{1}{F} \]

2. **Define Each Symbol in the Formula**:
- **V**: This represents the image distance. It is the distance from the pole of the mirror to the image formed by the mirror. The sign of V depends on the type of mirror and the position of the image (real or virtual).

- **U**: This denotes the object distance. It is the distance from the pole of the mirror to the object being reflected. Similar to V, the sign of U also depends on the type of mirror and the position of the object (in front of the mirror or behind it).

- **F**: This is the focal length of the spherical mirror. It is the distance from the pole of the mirror to the focal point, where parallel rays of light either converge (in concave mirrors) or appear to diverge from (in convex mirrors). The sign of F is also determined by the type of mirror.

3. **Sign Conventions**:
When using the spherical mirror formula, it is important to apply the proper sign conventions:
- For concave mirrors, F is negative, and V is positive for real images and negative for virtual images.
- For convex mirrors, F is positive, and V is always negative since virtual images are formed behind the mirror.