A converging lens is used to form an image on a screen. When the upper half of the lens is covered by an opaque screen

Options

A. half the image will disappear
B. complete image will disappear
C. intensity of image will decrease
D. intensity of image will increase

Explanation

To solve the problem, we need to understand the behavior of light as it passes through a converging lens and how covering half of the lens affects the image formed on the screen.

### Step-by-Step Solution:

1. **Understanding the Converging Lens**:
A converging lens (convex lens) bends light rays that pass through it so that they converge at a point known as the focal point. When an object is placed in front of a converging lens, it forms an image on the opposite side of the lens.

**Hint**: Remember that a converging lens focuses light rays to form an image.

2. **Ray Diagram**:
Draw a ray diagram showing the object, the lens, and the image formed on the screen. Indicate the direction of light rays coming from the object, passing through the lens, and converging to form the image.

**Hint**: Use at least two rays from the object to show how they converge after passing through the lens.

3. **Covering Half of the Lens**:
When the upper half of the lens is covered with an opaque screen, the lower half of the lens is still functional. Light rays from the object can still pass through the lower half of the lens and converge to form an image.

**Hint**: Visualize how the light rays would behave when only half of the lens is available for light to pass through.

4. **Effect on the Image**:
Since only half of the lens is used, the image will still be formed, but it will be less intense. The intensity of the image decreases because fewer light rays are contributing to the formation of the image on the screen.

**Hint**: Think about how the brightness of the image is affected by the amount of light that reaches the screen.

5. **Conclusion**:
The image will not disappear entirely; rather, it will be present but with reduced brightness (intensity). Therefore, the correct conclusion is that the intensity of the image will decrease when the upper half of the lens is covered.

**Hint**: Consider the relationship between the number of light rays and the brightness of the image.

### Final Answer:
When the upper half of the converging lens is covered by an opaque screen, the complete image will not disappear, but the intensity of the image will decrease.