"Magical Eyes" colorful light PPT courseware

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"Magical Eyes" colorful light PPT courseware

Two convex lenses with the same diameter have focal lengths of 8cm and 16cm respectively. Which lens deflects light more? What conclusions can you draw from this? If you examine the concavity and convexity of the lens again, what other conclusions can you draw?

Conclusion: The more convex the convex lens, the stronger the refractive power!

How do we see objects?

in conclusion:

1. The objects we see are inverted and reduced real images formed through the lens.

2. The lens is equivalent to a convex lens, and the retina is equivalent to a light screen.

Guess: How do we see distant objects as well as nearby objects?

Myopia

Some people have difficulty seeing distant objects. They have to put the object closer to their eyes to see clearly.

Myopia occurs when the lens is too convex, causing light to focus in front of the retina.

Correction: Use a concave lens to first diverge the light, and then converge it on the retina through the lens.

long sighted

Some people have difficulty seeing close objects. They have to place the objects further away from their eyes to see them clearly.

Hyperopia is when the lens is too flat, and objects are refracted by the lens and appear behind the retina.

Correction: Use a convex lens to first focus the light, and then focus it on the retina through the lens.

Prescription of glasses

1. The power of glasses is 100 times the reciprocal of the focal length of the lens.

2. The power of convex lenses (lenses for farsightedness) is positive, and the power of concave lenses (lenses for nearsightedness) is negative.

Structure and working principle of microscope

Principle: The object first passes through the objective lens to form a magnified real image, and then passes through the eyepiece to form a magnified virtual image. Small objects can be seen clearly after the second magnification.

telescope

Principle: A telescope is similar to a microscope and is also composed of two sets of convex lenses, namely the objective lens and the eyepiece. Different from a microscope, the purpose of the objective lens on a telescope is to make distant objects form a real image near the focus, and the eyepiece acts like a magnifying glass to magnify this image.

Slide projectors and projectors

Principle: The object is located between one focal length and twice the focal length to form an inverted magnified real image.

think:

1. How should the slides be placed during the show?

2. Are the imaging conditions of slide projectors and projectors exactly the same?

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"Magical Eyes" Colorful Light PPT Courseware 4:

"Magical Eyes" Colorful Light PPT Courseware 4 Review the past and learn the new ① Magnifying glass ② Microscope Optical microscope: The focal length of the objective lens is very small. The specimen is between one and twice its focal length, and a magnified inverted real image is formed through the objective lens; this image is in the eyepiece. Within multiple focal lengths, through...

"Magical Eyes" Colorful Light PPT Courseware 3:

"Magical Eyes" Colorful Light PPT Courseware 3 Two convex lenses with the same diameter, their focal lengths are 8cm and 16cm respectively. Which lens deflects light more? What conclusions can you draw from this? Then check the concave and convex degree of the lens, you can also get...

"Magical Eyes" Colorful Light PPT Courseware 2:

"Magical Eyes" Colorful Light PPT Courseware 2

What are the rules of imaging by convex lenses?

When u>2f, it becomes an inverted, reduced, real image, and the image and the object are on opposite sides of the lens.

when f

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Update Time: 2024-11-23

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