"Lens" Lens and its application PPT

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"Lens" Lens and its application PPT

Part One: Preview Perception

1. Convex lenses and concave lenses

1. Convex lens.

Middle _____edge_____.

2. Concave lens.

Middle _____edge_____.

3. Several terms for lenses (as shown in the picture).

(1) Optical center.

The __________ of the lens.

(2) Main optical axis.

A straight line through __________ and the sphere __________.

2. The effect of lens on light

1. Convex lens.

It has a __________ effect on light.

2. Concave lens.

It has a __________ effect on light.

3. Focus and focal length

1.Focus

After the light _____ on the main optical axis is refracted by the convex lens, it _____ on a certain point on the main optical axis.

2. Focal length.

The distance from the focus to _____.

Lens PPT, Part 2: Interactive Classroom Understanding

Three special rays in lens drawing

[Example] As shown in the figure, two rays parallel to the main optical axis and passing through the optical center are incident on the convex lens, and the refracted rays of the two rays are drawn.

Tip: To answer this question, proceed as follows:

Analysis: According to the convergence effect of convex lenses on light, that is, after the light rays parallel to the main optical axis are refracted by the convex lens, the refracted light passes through the focus on the other side of the convex lens, and the propagation direction of the light passing through the optical center of the convex lens does not change.

Answer: As shown in the picture

Lens PPT, Part 3: Try the application

1. Convex lenses and concave lenses

1. Cross-sectional views of some lenses are shown in the figure. Among these lenses,

(1) The convex lens is _______________. From the external characteristics, their common feature is _______________.

(2) The concave lens is _______________. From the external characteristics, their common feature is _______________.

2. The effect of lens on light

2. Schematic diagrams of several optical equipment are shown in the figure. Among them, the one that can diffuse light is ()

Convex lenses have a convergence effect on light, and concave lenses have a divergence effect on light. Concave lenses have the characteristics of being thin in the middle and thick at the edges, so only the lens in picture D is a concave lens, so it should be selected as D.

3. Regarding lenses, which of the following statements is correct ()

A. A convex lens has a focus, while a concave lens has no focus.

B. Convex lenses have a converging effect on light

C. Concave lenses can only diverge parallel light rays

D. Light rays parallel to the main axis must pass through the focus after passing through the concave lens

4. According to the propagation path of light, fill in the lens that meets the requirements in the dotted box in the figure.

3. Focus and focal length

5. A convex lens has _____ focal points, and the distance from the focal point to the optical center is called _____. The focal lengths on both sides of the same convex lens are _____, and the light converging effect of a convex lens with a short focal length is _____ (optional "strong" or "weak").

The convex lens has a converging effect on light. The light parallel to the main optical axis can converge to a point through the convex lens. This point is the focus of the convex lens. Because the light from both sides can be converged by the lens to a point on the other side, the convex lens has two focus points. The distance from the focus to the optical center of the lens is called the focal length. The focal lengths on both sides of the same convex lens are equal. A convex lens with a short focal length has a strong converging effect on light.

6. As shown in the figure, after a beam of light parallel to the main optical axis of the convex lens passes through the convex lens, it forms the smallest and brightest spot on the light screen. The focal length of this convex lens is _____cm.

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For more information about the PPT courseware "Lens and its Applications Lenses", please click the Lenses and Their Applications ppt lens ppt tag.

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Update Time: 2024-09-08

This template belongs to Physics courseware People's Education Edition Physics for Grade 8, Volume 1 industry PPT template

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