Lenses in life, lens knowledge points in life

The imaging law of the convex lens is as follows: when the object distance is within one time of the focal length, the upright and magnified virtual image is obtained; Between 1x and 2x focal lengths, a handstand, magnified real image is obtained; When outside of the double focal length, a handstand and zoomed out image is obtained.

The purpose of this experiment is to study and confirm this law. In the experiment, there is the following table:

The distance of the object is the nature of the image and the position of the image.

Upright or upside down Enlarge or shrink the virtual or real image Ipsilateral and opposite image distance from the object vu>2f Inverted reduction Real image opposite side f2f

u=f －－

u1 u (object distance) + 1 v (image distance) = 1 f (lens focal length).

The real image can be received by the light screen The virtual image is the vision of the person (not the hallucination), and the light screen cannot receive it without light entering the human eye.

Object distance is the distance from an object to a flat mirror.

Image distance is the distance from the image of an object to a flat mirror.

u>2f handstand zoom out real image opposite side f2f

u=f －－

u< F Upright magnification Virtual image ipsilateral u,v ipsilateral 1 u (object distance) + 1 v (image distance) = 1 f (lens focal length) < p>

The real image is an image that can be received with a light screen.

The virtual image does not exist, and the light screen cannot receive it, just like a magnifying glass.

Focal length is the height of the lens.

u>2f handstand shrinks.

u=2f handstand is equal to the size.

u=f does not image.

Object distance Image distance.

It is the distance between the absence of the body and the image.

Like the distance from the object.

Real images can be collected with a light screen. Illusion is an illusion of man. And no light enters the human eye. The opposite is true.

Object distance is the distance from an object to a flat mirror.

Image distance is the distance from the image of an object to a flat mirror.

The image of the small hole is the inverted reality, and the reflection in the water is the upright reality.

Don't your teachers care about you? Our teacher is very good, he acted in a little drama, and all the theorems and formulas have been solved, and I am so glad that I am so grateful to you, physics teacher!

However, the classmates upstairs have summarized in great detail, do more questions, and memorize them after comprehending them!

He is also a new junior high school student

In the daily process of learning, everyone has memorized a lot of knowledge points, and they must be very familiar with the knowledge points! Knowledge points can also be understood in popular terms as important content. Want a compiled list of knowledge?

Camera:

1. The lens is a convex lens;

2. The distance between the object and the lens (object distance) is greater than twice the focal length, and the real image is inverted and reduced.

Projector:

1. The lens of the projector is a convex lens;

2. The function of the plane mirror of the projector is to change the direction of light propagation (Note: To make the image larger for cameras and projectors, the lens should be close to the object, away from the film and screen. );

3. The distance between the object and the lens (object distance) is less than two times the focal length and more than one time the focal length, which becomes an inverted and magnified real image.

Magnifier:

1. The magnifying glass is a convex lens;

2. The distance between the magnifying glass and the object (object distance) is less than one time the focal length, and it becomes a magnified and upright virtual image; Note: To make the object larger, the magnifying glass should be kept away from the object.

1. Imaging characteristics of slide projector and projector: when the object is between one and two times the focal length of the convex lens, it becomes an inverted magnified real image. Note: Slides should be placed upside down (upside down, left and right).

2. Camera image point: The object is outside the double focal length of the convex lens, and becomes an inverted and reduced real image.

Idea 1: Take a solo photo after taking a group photo (the camera is closer to the person, and the camera obsca is extended).

Reflection 2: Some of the people in the camera are not in the lens (the camera is farther away from the person. Dark-box shortening).

3. Magnifying glass imaging features: the object is within one time of the focal length of the convex lens, and becomes an upright magnified virtual image. Ipsilateral to the image.

4. Microscope: It is composed of an eyepiece and an objective lens, the objective lens and the eyepiece are convex lenses, which magnify the object twice.

5. Telescope: It is composed of an eyepiece and an objective lens, the objective lens makes the object into a real image of shrinkage and inversion, and the eyepiece is equivalent to a magnifying glass and becomes a magnified image.

1. Magnifying glass: A convex lens with a short focal length can magnify small objects, but the object must be within one focal length of the convex lens, and the virtual image of magnification is upright.

2. Projector: The lens of the projector is equivalent to a convex lens, which uses the convex lens to form a magnified image.

3. Camera: The lens of the camera is equivalent to a convex lens, which is used to form a reduced image, and the light from the object eventually converges on the film to form a reduced one'An inverted image (a real image is formed by the convergence of actual light, and the film can be sensitive, so it can become a real image).

4. Microscope: It is composed of two convex lenses, and the real image of the observed object magnified by the objective lens falls within the focal length of the eyepiece, and the virtual image is magnified again (the objective lens of the microscope is equivalent to a projector, which becomes an inverted magnified real image; The eyepiece is equivalent to a magnifying glass, forming an upright magnified virtual image).

5. Telescope: The objective lens and eyepiece of the telescope are composed of convex lenses, and the distant objects pass through the objective lens to form a reduced real image, forming a magnified virtual image within the focal length of the eyepiece; The larger the objective, the brighter it appears to distant objects; The distance between the objective lens and the eyepiece should not be greater than the sum of the focal lengths of the two convex lenses; The objective lens in the telescope is equivalent to a camera, inverted, zooming out the real image; The eyepiece is equivalent to a magnifying glass, which is upright and magnifying the virtual image).

1. Slide projector and projector: The distance from the slide or projection to the convex lens is the object distance, and the distance from the lens to the screen is the image distance. 2. Camera:

The lens of a camera is equivalent to a convex lens, the distance from the scene to the lens is the object distance, and the distance between the lens and the film is the image distance. 3. Microscope: The eyepiece and the objective lens are both convex penetration, the objective lens is equivalent to a slide projector, and the eyepiece is equivalent to a magnifying glass.

It is two magnifications of the object, the objective lens becomes a magnifying real image, and the eyepiece becomes a magnifying virtual image. 4. Telescope: The eyepiece and objective lens are both convex lenses, the objective lens is equivalent to the camera, and the eyepiece is equivalent to the magnification realm.

1. Slide projector and projector:

Principle: When the object distance is between 1x focal length and 2x focal length, it becomes an inverted magnified real image, and the image distance is greater than the object distance.

For the screen to be upright, the slide must be played upside down. To make the image on the screen larger, the distance between the convex lens and the slide or slide should be reduced, and the screen should be kept away from the lens, i.e., the slide projector or projector should be kept away from the screen decay. The role of a flat mirror in a projector is to change the direction of light propagation.

2. Camera:

Principle: When the object distance is greater than 2 times the focal length, it becomes an inverted and reduced real image, and the image distance is between 1 times the focal length and 2 times the focal length.

To make the image on the film larger, the object distance should be reduced and the image distance should be increased, that is, the camera should be closer to the scene, and the distance between the lens and the film should be adjusted at the same time.

Bigger. 3. Microscope:

The magnification of the object by the microscope = the magnification of the object environment is taught by the magnification of the eyepiece.

4. Telescope: The eyepiece and the objective lens are both convex lenses, the objective lens is equivalent to the camera, and the eyepiece is equivalent to the magnification realm. When we see distant objects, the angle of view becomes larger when we look into the distance, so we can see very clearly.

The knowledge points of lenses in life are as follows:

Knowledge point 1: Camera.

1.Principle: Use convex lens to form an inverted and reduced real image.

2.Imaging characteristics: when taking pictures, the closer the lens is to the object, the farther the image is from the lens, and the larger the image is formed; The farther away the lens is from the object, the closer the image is to the lens, and the smaller the image is.

Knowledge point 2 Projector.

1.Principle: Use convex lens to form an inverted and magnified real image.

2.Imaging features.

1) The distance from the slide to the lens (object distance) is less than the distance from the lens to the screen (image distance).

2) The closer the slide is to the camera, the larger the image on the screen and the greater the distance from the image to the camera.

Knowledge point 3 Magnifying glass.

1.Principle: Place the magnifying glass lens in the appropriate position above the object, through the magnifying glass, we can see an upright, magnified virtual image.

2.Imaging features: (1) The image of the observed object is magnified. (2) The object and the image formed by the lens are on the same side of the lens. (3) The image cannot be presented on the light screen.

Knowledge point 4: Real image and virtual image.

1.Real image: The real image is formed by the convergence of actual light, which can be undertaken by the light screen, can make the film light-sensitive, can be observed with the eye, and the objects and images are distributed on both sides of the convex lens. The reality is all upside down.

2.Virtual image: The virtual image is not formed by the convergence of actual rays, but by the intersection of the reverse extension lines of refracted rays, which cannot be undertaken by the light screen, but can only be observed and seen by the eyes, and the object and image are located on the same side of the convex lens. The imaginary images are upright.

A lens is a refractor, and its refractive surface is a transparent body with two spheres (part of the sphere), or a sphere (part of the sphere) and one plane.

The lens is an optical element made of transparent material with a surface that is part of the spherical surface, and the lens is composed of several lenses, there are two kinds of plastic lenses (plastic) and glass lenses (glass), glass lenses are more expensive than plastics.

Usually the lens structure used in the camera is: 1P, 2P, 1G1P, 1G2P, 2G2P, 4G, etc., the more lenses, the higher the cost. Therefore, a good quality camera should use a glass lens, which has a better imaging effect than a plastic lens, and plays an important role in astronomy, military, transportation, medicine, art and other fields.

Lenses can be widely used in security, automotive, digital cameras, lasers, optical instruments and other fields, with the continuous development of the market, lens technology is more and more widely used. (lens) lenses are made according to the law of refraction of light. A lens is an optical element made of a transparent substance such as glass, crystal, etc.

A lens is a refractor, and its refractive surface is a transparent body with two spheres (part of the sphere), or a sphere (part of the sphere) and one plane. It forms both real and imaginary images.

A thin lens is a lens in which the thickness of the first part is large compared to the radius of curvature on both sides. In the early days, cameras were equipped with only one convex lens, so they were called "single lenses". With the development of science and technology, modern lenses have several convex and concave lenses of different forms and functions to form a converging lens, called "double lens".

The concave lens in the double lens plays the role of correcting various aberrations.