"Color of Objects" Light Phenomenon PPT Courseware 3

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"Color of Objects" Light Phenomenon PPT Courseware 3

1. Dispersion

1. The phenomenon that sunlight is decomposed into seven colors of light after passing through a prism is called dispersion of light.

2. White light is a mixture of seven monochromatic lights: red, orange, yellow, green, blue, indigo and violet.

Exchange and discussion

1. The law of refraction of light:

(1) When light is refracted, the refracted ray, incident ray, and normal are in the same plane, and the refracted ray and incident ray are located on both sides of the normal. The refraction angle changes with the change of the angle of incidence: when the angle of incidence increases, the angle of refraction also increases; when the angle of incidence decreases, the angle of refraction also decreases.

(2) When light is incident obliquely from the air into a transparent substance such as water or glass, the refraction angle is smaller than the incident angle; when light is incident obliquely into the air from a transparent substance such as water or glass, the refraction angle is greater than the incident angle.

2. As shown in the figure, draw the approximate position of the refracted ray.

When light is refracted on the two sides of the prism, it is deflected to the bottom twice. Different colors of light are deflected to different degrees.

Small exercise: 1. In 1666, the British physicist ______ used a prism to disperse sunlight.

2. After passing through a prism, sunlight is divided into seven color bands of ______, ______, ______, ______, ______, ______, ______. This is the ______ phenomenon.

3. The dispersion phenomenon of light shows that white light is mixed by ______.

4. A rainbow is caused by ______ of sunlight being spread by water droplets in the air.

5. Mao Zedong’s poem “Red, orange, yellow, green, indigo, blue, purple, who holds the colors and practices dancing in the air” mainly involves physical knowledge is ______.

2. Mixing of colors and lights

It was discovered that light of various other colors can be obtained by mixing red, green and blue light in appropriate proportions.

The three colors of red, green, and blue are called the "three primary colors of color."

3. Color of objects

When light strikes an object, part of the light is reflected by the object and part of the light is absorbed by the object. If the object is transparent, some light will still pass through the object. Different objects reflect, absorb and transmit different colors of light differently, so they appear in different colors.

1. Color of transparent objects

The color of a transparent object is determined by the colored light it transmits.

2. Color of opaque body

The color of an opaque object is determined by the colored light it reflects.

Black objects absorb various colors of light and do not reflect light at all.

White objects reflect various colors of light.

Small exercises: 1. The color of colored transparent objects is determined by ______, and the color of colored opaque objects is determined by ______.

2. The color of an object that can absorb various colors of light is ______.

3. The color of an object that can reflect light of various colors is: ( )

A. White B. Colorless

C. Black D. This color does not exist

4. When a beam of light shines on a piece of paper and the paper appears red, then the relationship between this beam of light and the paper is: ( )

A. Red light, white paper B. White light, red paper

C. Red light, red paper D. The above situations are possible.

Classroom testing

1. The color of a transparent object is determined by its ______ color light. For example, the red glass I saw is because the red glass allows _______ in the sunlight to pass through, while other types of color light are absorbed by the red glass.

2. The three primary colors of light are ____________.

3. The three primary colors of pigments are ____________.

3. Which of the following statements is correct ( )

A. White light is one of the seven colors of light. B. Any color light can cause dispersion of light when it shines obliquely on a prism.

C. Blue light cannot be obtained by mixing light. D. The formation of rainbow is the dispersion of light.

4. When there is no other light, the green light emitted by the stage spotlight shines on the actor wearing a white top and red skirt. When the audience sees her ( )

A. The whole body is green B. The top is green and the skirt remains unchanged

C. The upper body is green and the skirt is purple. D. The upper body is green and the skirt is black.

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For more information about the "Color of Light Phenomena Objects" PPT courseware, please click on the "Color of Light Phenomenon Objects" PPT tab.

"Color of Objects" Light Phenomenon PPT Courseware 2:

"Color of Objects" Light Phenomenon PPT Courseware 2 Review and Consolidation: 1. The law of reflection of light 2. The law of refraction of light 3. Characteristics of plane mirror imaging 4. The difference between real image and virtual image Orientation mark 1. Understand the dispersion phenomenon and know the characteristics of colored light The three primary colors are different from the three primary colors of paint...

"Color of Objects" PPT courseware on light phenomena:

"The Color of Objects" Light Phenomenon PPT Courseware [Experience] Dispersion of Light Activity 1: Prepare water, a container, a plane mirror, and a paper screen. Place the device as shown in the figure. Adjust the mirror angle to refract sunlight onto the white paper screen and observe the light on the paper screen. color. Activity 2: Put the CD in the sun..

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Update Time: 2024-10-19

This template belongs to Physics courseware Beijing Normal University eighth grade physics volume one industry PPT template

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