# Converging lens experiment

• jnimagine
In summary, the person had previously asked a similar question about an experiment with a converging lens and a candle. This time, they found that when the candle was placed at the focal point, an image appeared at 136cm, which should not happen according to theory. They wonder if this is also caused by the 3-D effect of the candle, but it is unlikely as the mirror in the previous experiment was too small to cause spherical aberration. The same principles apply to both mirrors and lenses, and it is possible that a measurement error could have caused the unexpected result.
jnimagine
hi i posted the same sort of question a few times before but this time it's a little different
we did an experiment with a converging lens and a candle to find an image. When the candle was placed at the focal point, which was 16.3cm, an image appeared at 136cm. I know in theory, no image should be appearing here. Last time when i asked the same question but with concave mirrors, some of the answers i got were that it was caused by the 3-D of the candle and spherical aberrations. But spherical aberration is not likely have caused it because the mirror was too small to cause that. So my question is, is it the same for a converging lens? the reason an image appears there is because of the three-dimensionality of the candle?

All the same principles apply to a converging lens that apply to a converging mirror. It seems very unlikely that this is purely a 3-D effect. Some of the flame would have to be more than 18cm from the lens to get a sharp image at 136cm if the focal length is indeed 16.3cm. Some distance measurement is probably a bit off, but that's the way real measurements are, subject to a certain amount of error.

Thank you for sharing your experiment with us. It is always interesting to see how different setups can produce unexpected results.

Based on your description, it seems that the image appearing at 136cm is due to the three-dimensionality of the candle. This is known as the "real image" of the candle, which is formed when the light rays from the candle converge at a point beyond the focal point of the lens.

Spherical aberration is not likely the cause in this case, as you mentioned, since the lens you used was too small to produce this effect. However, there are other factors that can contribute to a distorted image, such as chromatic aberration or astigmatism. These are caused by the lens not being perfectly symmetrical, and can result in a blurred or distorted image.

It is also possible that your experimental setup was not precise enough, leading to some errors in the measurements. I would suggest repeating the experiment multiple times and making sure all the variables are controlled to get a more accurate result.

Overall, the image appearing at 136cm is most likely due to the three-dimensionality of the candle and not any aberrations of the lens. I hope this helps clarify your results. Keep up the good work in your scientific explorations!

## 1. What is a converging lens experiment?

A converging lens experiment is an experiment designed to study the properties of a converging lens, such as its focal length, magnification, and image formation. It involves using a converging lens to focus light rays and produce an image, and then manipulating the lens and its distance from the object to observe changes in the image.

## 2. What is the purpose of a converging lens experiment?

The purpose of a converging lens experiment is to understand the behavior and characteristics of a converging lens, which is a commonly used optical element in many devices such as cameras, telescopes, and microscopes. The experiment allows us to study how a converging lens bends and focuses light rays to create an image, and how the properties of the lens affect the image formed.

## 3. What materials are needed for a converging lens experiment?

The materials needed for a converging lens experiment include a converging lens, a light source, an object to be viewed, a screen to capture the image, and a ruler or measuring tool to determine distances. Optional materials may include a lens holder, a light source holder, and a mirror to reflect the light rays.

## 4. How does the focal length of a converging lens affect the image formed?

The focal length of a converging lens is the distance from the lens to the point where light rays converge and form an image. As the focal length changes, the position and characteristics of the image formed also change. When the focal length is shorter, the image is larger and closer to the lens. When the focal length is longer, the image is smaller and farther away from the lens.

## 5. What are some applications of a converging lens experiment?

A converging lens experiment has many applications in the fields of physics and engineering. It is used to study and understand the properties of lenses, which are essential components in various optical devices. The experiment is also used to determine the focal length of a lens, which is important in designing and optimizing optical systems for different applications.

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