"Lens and Vision" PPT

Description

"Lens and Vision" PPT

Part One: Lenses in Life

Observe the following lenses and talk about the characteristics of these lenses

Lenses that are thick in the middle and thin on the edges

——convex lens

Lenses that are thin in the middle and thick on the edges

--concave lens

Lens and vision PPT, part 2: four elements of convex lens

The converging effect of convex lens on light

[Observation] A beam of parallel light passes through a convex lens___________.

1. The point where parallel light rays converge through a convex lens is called the ______ of the convex lens, represented by the letter ______; there is a ______ on each side of the convex lens.

2. The ______ from the focus to the optical center of the convex lens is called ______, and ______ represents the two focal lengths on both sides ____________.

Lens optical path diagram

1. How to create optical path diagram of convex lens

①After the light rays parallel to the main optical axis are refracted by the convex lens, the refracted light rays pass through the focus;

② After the light passing through the optical center passes through the lens, the propagation direction remains unchanged;

③After the light passing through the focus is refracted by the convex lens, the refracted light is parallel to the main optical axis.

Lenses and vision PPT, Part 3: The divergent effect of concave lenses on light

1. The ______ rays of light that are parallel to the main optical axis after passing through the concave lens ______ intersect at one point, but their ____________ lines intersect at one point on the main optical axis. This point is also called the ______ of the concave lens, because it It is not the actual point of convergence of light, so it is called ______ focus.

2. Three special rays of light path diagram of concave lens

①After the light rays parallel to the main axis are refracted by the concave lens, the reverse extension line of the refracted light rays passes through the focus;

② After the light passing through the optical center passes through the lens, the propagation direction remains unchanged;

③After the extension line of the incident light passes through the focus and is refracted by the concave lens, the refracted light is parallel to the main optical axis.

Lens and Vision PPT, Part 4: Expansion

convergence and divergence

The convergence and divergence of convex lenses and concave lenses cannot be judged simply based on whether the incident light rays intersect after being refracted by the lens. The true understanding of divergence and convergence should be whether the irradiation range of light after refraction by the lens is larger or smaller than the original irradiation range without refraction by the lens. If it increases, it is divergence; if it decreases, it is convergence.

Thoughts and Discussions

Can you make fire using ice and sunlight?

Take a piece of ice, grind it into a convex lens, and place it in the sun to focus the sunlight into a point to light a fire.

Lens and Vision PPT, Part 5: Classroom Training

1. Fill in the appropriate lenses in each light path shown in the figure.

2. What can diffuse light ( )

A． Convex lens Convex mirror B. Convex mirror Concave lens

C. Convex lens Concave lens D. concave lens concave mirror

3. Place a lens in each of the dotted boxes shown in Figures A and B. The two beams of light emitted from the luminous point S pass through the lens in the direction shown in the figure, then ( )

A． A is a concave lens, B is a convex lens

B. A and B are both convex lenses

C. A is a convex lens, B is a concave lens

D． A and B are both concave lenses

Keywords: Zhejiang Education Edition seventh grade science PPT courseware for the second volume free download, lens and vision PPT download, .PPT format;

For more information about the "Lens and Vision" PPT courseware, please click on the "Lens and Vision ppt" tab.

"Lens and Vision" PPT download:

"Lens and Vision" PPT Download Part One: Pre-class Thoughts 1. How to roughly measure the focal length of a convex lens? Face the convex lens to the sun, use a piece of white paper as a light screen on the other side of the convex lens, so that the convergence point of the light appears on the light screen, and use a scale to measure...

"Lens and Vision" PPT courseware:

"Lens and Vision" PPT courseware Part 1: Think about it 1. Have you ever encountered or used lenses in your life? Myopia glasses, magnifying glass, telescope ------- 2. What are the common characteristics of different lenses? Materials (glass, resin, crystal, etc.) various...

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Update Time: 2024-09-28

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