Under what condition, a concave lens can make a real image.

Explanation

To determine the conditions under which a concave lens can produce a real image, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Lens Formula**:
The lens formula is given by:
\[
\frac{1}{f} = \frac{1}{v} - \frac{1}{u}
...