The Image Formed By A Concave Lens Is Always Virtual Erect And Smaller Than The Object Explain Any Case One Case With The Help Of A Diagram
The Image Formed by a Concave Lens: Understanding the Basics
A concave lens, also known as a diverging lens, is a type of lens that spreads out light rays as they pass through it. In this article, we will discuss the properties of the image formed by a concave lens, including its virtual, erect, and smaller nature compared to the object.
What is a Concave Lens?
A concave lens is a type of lens that is thinner in the middle than at the edges. It is also known as a diverging lens because it diverges or spreads out light rays as they pass through it. The concave lens is made up of two curved surfaces, one convex and one concave, which are joined together to form a single lens.
Properties of the Image Formed by a Concave Lens
The image formed by a concave lens is always virtual, erect, and smaller than the object. This is because the concave lens spreads out light rays as they pass through it, resulting in a virtual image that is formed behind the lens.
Virtual Image
A virtual image is an image that is formed behind the lens and cannot be projected onto a screen. It is a result of the light rays being diverged or spread out by the concave lens. The virtual image is formed by the light rays that are not actually converging at a point, but rather appear to be converging at a point.
Erect Image
An erect image is an image that is formed with the same orientation as the object. In the case of a concave lens, the image is always erect, meaning that it is formed with the same orientation as the object.
Smaller Image
A smaller image is an image that is formed that is smaller than the object. In the case of a concave lens, the image is always smaller than the object.
Case Study: Image Formed by a Concave Lens
Let's consider a case study to understand how a concave lens forms an image. Suppose we have an object placed 10 cm in front of a concave lens with a focal length of -5 cm. The object is a small ball that is 2 cm in diameter.
Diagram
Here is a diagram to illustrate the image formed by the concave lens:
+---------------+
| Object (2cm) |
+---------------+
|
|
v
+---------------+
| Concave Lens |
| (focal length |
| -5 cm) |
+---------------+
|
|
v
+---------------+
| Image (virtual)|
| (erect and smaller)|
+---------------+
Explanation
In this case study, the object is placed 10 cm in front of the concave lens. The light rays from the object pass through the concave lens and are diverged or spread out. The image formed by the concave lens is virtual, erect, and smaller than the object.
Calculating the Image Distance
To calculate the image distance, we can use the lens equation:
1/f = 1/do + 1/di
where f is the focal length, do is the object distance, and di is the image distance.
Rearranging the equation to solve for di, we get:
1/di = 1/f - 1/do
Substituting the values, we get:
1/di = 1/(-5) - 1/10 1/di = -0.2 - 0.1 1/di = -0.3
di = -1/0.3 di = -3.33 cm
The negative sign indicates that the image is formed behind the lens.
Conclusion
In conclusion, the image formed by a concave lens is always virtual, erect, and smaller than the object. This is because the concave lens spreads out light rays as they pass through it, resulting in a virtual image that is formed behind the lens. The case study discussed above illustrates how a concave lens forms an image, and the calculations demonstrate how to determine the image distance.
Key Takeaways
- A concave lens is a type of lens that spreads out light rays as they pass through it.
- The image formed by a concave lens is always virtual, erect, and smaller than the object.
- The concave lens is made up of two curved surfaces, one convex and one concave, which are joined together to form a single lens.
- The image distance can be calculated using the lens equation.
References
- [1] Hecht, E., & Zajac, A. (2003). Optics. Addison-Wesley.
- [2] Goldsmith, J. (2008). Optics. Pearson Education.
- [3] Serway, R. A., & Jewett, J. W. (2018). Physics for Scientists and Engineers. Cengage Learning.
Q&A: Understanding the Image Formed by a Concave Lens
In our previous article, we discussed the properties of the image formed by a concave lens, including its virtual, erect, and smaller nature compared to the object. In this article, we will answer some frequently asked questions about the image formed by a concave lens.
Q: What is the focal length of a concave lens?
A: The focal length of a concave lens is negative, indicating that the lens spreads out light rays as they pass through it.
Q: How does the image distance change with the object distance?
A: The image distance changes with the object distance according to the lens equation: 1/f = 1/do + 1/di. As the object distance increases, the image distance decreases.
Q: Can a concave lens form a real image?
A: No, a concave lens cannot form a real image. The image formed by a concave lens is always virtual, meaning that it is formed behind the lens and cannot be projected onto a screen.
Q: What is the magnification of a concave lens?
A: The magnification of a concave lens is always less than 1, indicating that the image is smaller than the object.
Q: Can a concave lens be used to form a magnified image?
A: No, a concave lens cannot be used to form a magnified image. The magnification of a concave lens is always less than 1, indicating that the image is smaller than the object.
Q: How does the image formed by a concave lens change with the wavelength of light?
A: The image formed by a concave lens does not change with the wavelength of light. The concave lens spreads out light rays of all wavelengths equally, resulting in a virtual image that is formed behind the lens.
Q: Can a concave lens be used to form an image of a distant object?
A: Yes, a concave lens can be used to form an image of a distant object. However, the image will be virtual, erect, and smaller than the object.
Q: How does the image formed by a concave lens change with the angle of incidence?
A: The image formed by a concave lens does not change with the angle of incidence. The concave lens spreads out light rays of all angles equally, resulting in a virtual image that is formed behind the lens.
Q: Can a concave lens be used to form an image of a three-dimensional object?
A: No, a concave lens cannot be used to form an image of a three-dimensional object. The image formed by a concave lens is always two-dimensional, meaning that it is formed as a flat image behind the lens.
Q: How does the image formed by a concave lens change with the temperature of the lens?
A: The image formed by a concave lens does not change with the temperature of the lens. The concave lens spreads out light rays of all temperatures equally, resulting in a virtual image that is formed behind the lens.
Q: Can a concave lens be used to form an image of a moving object?
A: Yes, a concave lens can be used to form an image of a moving object. However, the image will be virtual, erect, and smaller than the object.
Conclusion
In conclusion, the image formed by a concave lens is always virtual, erect, and smaller than the object. The concave lens spreads out light rays as they pass through it, resulting in a virtual image that is formed behind the lens. The Q&A section above answers some frequently asked questions about the image formed by a concave lens.
Key Takeaways
- A concave lens is a type of lens that spreads out light rays as they pass through it.
- The image formed by a concave lens is always virtual, erect, and smaller than the object.
- The concave lens is made up of two curved surfaces, one convex and one concave, which are joined together to form a single lens.
- The image distance can be calculated using the lens equation.
- The magnification of a concave lens is always less than 1, indicating that the image is smaller than the object.
References
- [1] Hecht, E., & Zajac, A. (2003). Optics. Addison-Wesley.
- [2] Goldsmith, J. (2008). Optics. Pearson Education.
- [3] Serway, R. A., & Jewett, J. W. (2018). Physics for Scientists and Engineers. Cengage Learning.