A point source of light is placed on the principal axis between F and 2F of a concave lens. On the other very far , a screen is placed perpendicular to principal axis. As the screen is brought close towards lens

Options

A. the light intensity on screen continuously decreases
B. the light intensity on screen continuously increases
C. the light intensity on screen first increases, then decreases
D. the light intensity on screen first decreases, then increases

Explanation

To solve the problem, we need to analyze the behavior of light as it passes through a concave lens when a point source of light is placed between F (the focal point) and 2F (twice the focal length).

### Step-by-Step Solution:

1. **Understanding the Setup**:
- We have a concave lens, which is a diverging lens.
- A point source of light is placed on the principal axis between the focal point (F) and twice the focal point (2F).
- A screen is placed very far from the lens, perpendicular to the principal axis.

2. **Behavior of Light through a Concave Lens**:
- When light rays emanate from the point source, they pass through the concave lens.
- The concave lens diverges these rays, making them appear to come from a virtual image located on the same side as the object (the point source).

3. **Position of the Virtual Image**:
- Since the point source is between F and 2F, the virtual image formed by the concave lens will be located on the same side as the object (the point source) and will be virtual and upright.

4. **Moving the Screen Closer**:
- As the screen is brought closer to the lens, it intercepts more diverging rays from the lens.
- Since the concave lens diverges the rays, the intensity of light on the screen increases as more rays are captured by the screen.

5. **Conclusion**:
- Therefore, as the screen is brought closer to the lens, the intensity of light on the screen continuously increases.

### Final Answer:
The intensity of light on the screen continuously increases as the screen is brought closer to the concave lens.