Can anyone tell me the law of convex lens imaging

When the object is placed outside the focal point, it becomes an inverted real image on the other side of the convex lens, and there are three types of real images: reduced, equal size, and magnified. The smaller the object distance, the larger the image distance, and the larger the real image. The object is placed in focus, and the virtual image is magnified upright on the same side of the convex lens.

The smaller the object distance, the smaller the image distance, and the smaller the virtual image.

In optics, an image formed by the convergence of actual light rays is called a real image; Otherwise, it is called an imaginary image. Experienced physics teachers, when talking about the difference between real and virtual images, often mention such a way to distinguish between real and virtual images: "Real images are inverted, while virtual images are upright."

The so-called "upright" and "inverted" are, of course, relative to the original image. When the distance between the object and the convex lens is greater than the focal length of the lens, the object becomes an inverted image, and when the object approaches the lens from a distance, the image gradually becomes larger, and the distance from the image to the lens also gradually increases; When the distance between the object and the lens is less than the focal length, the object becomes an enlarged image, which is not the convergence point of the actual refracted rays, but the intersection point of their reverse extension lines, which cannot be received by the light screen, and is a virtual image. When the distance between the object and the lens is greater than the focal length, the object becomes an inverted image, which is formed by the convergence of the light from the candle to the convex lens through the convex lens, which is the convergence point of the actual light, which can be undertaken by the light screen, and is a real image.

When the distance between the object and the lens is less than the focal length, the object becomes an upright virtual image.

To put it simply, 1) outside of the double focal length, inverted to reduce the real image;

1x focal length to 2x focal length, inverted magnification of real image;

Within one time of the focal length, the virtual image is magnified upright;

The real image and the image are on the opposite side of the convex lens, and the virtual image is on the same side of the convex lens.

There is a section on convex lenses in the textbook.

There is an experiment of convex lens, which is the imaging law of convex lens.

1. First of all, look at the diagram to figure out what the focal length (f), object distance (u) and image distance (f) refer to.

2u>2f Inverted zoomed-out real image camera fu>f Inverted magnified real image Projector, movie F>2F

u

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Analysis: Imaging Rules:

When you are greater than 2f, it becomes an inverted shrinking real image, like in f.

between 2F; When U is between F and 2F, it becomes an inverted magnified image, like in.

2F Outside; When U is less than F, the virtual image is magnified upright;

When u=2f, it becomes a large real image such as an inverted stand, like at 2f;

When u=f, no imaging is performed.

Law of change: when the real image is formed: the near image of the object becomes larger, and the distant image of the object becomes smaller;

For example, when taking pictures, how should I adjust the image on ** if I want to make it bigger?

Solution: If you want to make the image larger, according to the above change law, the camera should be closer to the person being photographed (object closer), and at the same time, the lens should be stretched forward and farther away from the negative (image far), so that the image can become larger.

When the image becomes a virtual image, the near image of the object becomes smaller, and the distant image of the object becomes larger;

For example, when reading a book with a magnifying glass, how should I adjust the words I see to make the words I see bigger?

Solution: The magnifying glass should be farther away from the word (far away), so that the word can be bigger (like bigger);

When forming a real image, the distance between the image and the object should not be less than 4F.

For example, if the focal length of the convex lens is 20 cm, and the candle and the light screen are placed on the light fixture base, and the distance between the two is 70 cm, no matter how you move the convex lens in the middle, you will not be able to get a real image on the light screen. Because 70cm is less than 80cm.

Convex lens imaging rules:

Regular vertical pitch early 1: When the object distance is greater than 2 times the focal length, the image distance is between 1 times the focal length and 2 times the focal length, and it becomes an inverted and reduced real image. At this time, the image distance is smaller than the object distance, the image is smaller than the object, and the object image is on the opposite side.

Rule 2: When the object distance is equal to 2 times the focal length, the image distance is also 2 times the focal length, forming an inverted and equal-sized real image. At this time, the object distance is equal to the image distance, the image and the object are equal in size, and the object is on the opposite side.

Rule 3: When the object distance is less than 2 times the focal length and greater than 1 times the focal length, the image distance is greater than 2 times the focal length, and it becomes an inverted and magnified real image. At this time, the image distance is greater than the object distance, like the reed year is larger than the object, and the object is like the opposite side.

Convex lens imaging has the following rules:

Rule 1: When the object distance is greater than 2x the focal length, the image distance is between 1x the focal length and 2x the focal length, and it becomes an inverted and reduced real image. At this time, the image distance is smaller than the object distance, the image is smaller than the object, and the object image is on the opposite side.

Rule 2: When the object distance is equal to 2 times the focal length, the image distance is also 2 times the focal length, forming an inverted, equal size solid and grinding image. At this time, the object distance is isotonic in the image distance, the image and the object are equal in size, and the object is on the opposite side.

Rule 3: When the object distance is small and the object distance is 2 times the focal length and greater than 1 times the focal length, the image distance is greater than 2 times the focal length, and it becomes an inverted and magnified real image. At this time, the image distance is greater than the object distance, the image is larger than the object, and the object image is opposite.

Rule 4: When the object distance is equal to 1 times the focal length, it will not be imaged, and it will be emitted as parallel light.

Rule 5: When the object distance is less than 1 times the focal length, it becomes an upright and magnified virtual image. At this time, the image distance is greater than the object distance, the image is larger than the object, and the object image is on the same side.

Applications of Convex Lenses:

The lens of the camera is a convex lens, the scene to be illuminated is the object, and the film is the screen. The light shining on the object is diffusely reflected and the image of the object is formed on the final film through the convex lens; The film is coated with a layer of light-sensitive substance, which undergoes a chemical change after **, and the image of the object is recorded on the film.

The relationship between object distance and image distance is exactly the same as that of convex lenses. As the object approaches, the image gets farther and farther away, larger and larger, and finally becomes a virtual image on the same side. The object distance increases, the image distance decreases, and the image becomes smaller; The object distance decreases, the image distance increases, and the image becomes larger.

One double focal length is divided into virtual and real, and two times the focal length is divided into size.

The five graphs of the imaging law of convex lenses are as follows:

1. Outside of the double focal length, invert the real image to zoom in.

2. Double focal length and other sizes.

3. From one time of the focal length to two times the focal length, invert and magnify the real image.

4. Double the focal length is not imaging.

5. Within one time of the focal length, the virtual image should be magnified upright.

u is the object distance, that is, the distance from the object to the lens; v is the image distance, that is, the distance from the image to the lens; f is the focal length.

Regularity: When u>2f, f2f

Inverted, magnified, real image, application: projector, slide projector imaging principle.

When u f, the image distance can be ignored and become an upright, magnified, and virtual image. Application: Magnifier principle.

When u=2f, v=2f

into an inverted handstand, equal size, real image.

In addition, there are microscopes, eyepieces and objective lenses for telescopes and hail mirrors (Keplerian type).