"Lens" Lens and its applications PPT courseware 3

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"Lens" Lens and its applications PPT courseware 3

The mirrors we learned about in the chapter on light phenomena include: (reflective)

Plane mirror, concave mirror, convex mirror

The following mirrors also exist in real life: (can transmit light)

Magnifying glass, myopia glasses, reading glasses, telescope, microscope, periscope

The lenses of magnifying glasses, cameras, projectors and other instruments mentioned above are all composed of lenses. Today, we will study lenses.

Lens: a mirror that transmits light

1. Identify and classify the following lenses:

2. The main optical axis (main axis) and optical center of the lens

Note: The direction of propagation of light that passes through the optical center remains unchanged.

Note: For thin lenses of the same texture, the optical center is at its geometric center.

2. The effect of lens on light

Exploration: Use parallel light to pass through a convex lens and a concave lens in sequence to observe the phenomenon.

The effect of prism on light

The light passing through the prism is refracted twice by the prism and then deflected toward the thicker end of the prism.

1. The effect of convex lens on light

Convex lenses converge light, so convex lenses are also called converging lenses.

2. The effect of concave lens on light

Concave lenses diverge light, so they are also called divergent lenses.

Knowledge extension: The meaning of "convergence" and "divergence" in optics.

The refracted light ray is closer to the main optical axis relative to the extension line of the original light ray, which is called "convergence".

The refracted light ray is far away from the main optical axis relative to the extension line of the original light ray, which is called "divergence".

Focus and focal length of lens:

1. There is a focus F (real focus) on the left and right sides of the convex lens, and each has a focal length.

2. There is a focus F (virtual focus) on the left and right sides of the concave lens, and each has a focal length.

4. Research: Determine the focal length of a convex lens

step:

1. Place a lens facing the sun;

2. Place another piece of paper on the other side of the convex lens;

3. Change the distance between the lens and the paper until the spot on the paper becomes the smallest and brightest;

4. Measure the distance from the smallest and brightest spot to the convex lens

life physics society

1. The staff exploring in the Arctic have lost fire. Please find a way to obtain fire for the explorers working in the ice and snow, and solve their worries.

2. Do you know who caused the trouble?

One day, after a heavy rain, the puppy Beibei was lying on the hay in his nest. The top of the kennel was built with thin plastic to protect it from the rain. At this time, a layer of water had accumulated on the plastic. The sky was sunny, and the sun shone through the water on the dog, making it very warm and comfortable. , suddenly, Beibei's tail caught fire, making it jump up and down in pain...

3. When going on an outing, why can't you throw the beverage bottles with liquid left in the woods?

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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.

"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...

"Lens and Vision" PPT:

"Lens and Vision" PPT Part One Content: Lenses in Life Observe the following lenses and talk about the characteristics of these lenses Thick in the middle Lenses with thin edges Convex lenses Thin in the middle Lenses with thick edges Concave lenses... ... Lens and vision PPT, second...

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Update Time: 2024-06-11

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

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