Hello, I'm a student who is about to take the senior high school entrance examination ~ ~ What's the focus of physics and optics?

1, light can propagate in a vacuum or transparent medium without medium.

2. Light travels in a straight line in the same uniform medium or vacuum.

The speed of light is the fastest in vacuum, slower in air, slower in liquid and slowest in solid.

Light will be reflected when it hits the surface of any object, and any reflection must follow China's reflection method.

5 The reflection law of light is 1, and both incident light and reflected light are on both sides of the normal; The incident light, reflected light and normal are in the same plane, and the reflection angle must be equal to the incident angle.

6 reflection is divided into specular reflection and slow reflection.

7. The light path in the light reflection phenomenon is reversible.

8. The images of plane mirror images are equal in size; The size of the image is determined by the size of the object, regardless of the object distance.

The distance from the object to the mirror is the same as the distance from the image to the mirror.

10 plane mirror becomes an isometric virtual image.

1 1 Convex mirror has divergent effect on light, and concave mirror has convergent effect on light.

12 When light obliquely enters another medium from one medium, the light will be deflected, which is called light refraction.

13 Black objects absorb all light, white objects reflect all light, and other colors absorb other colors and reflect their own light.

The three primary colors of 13 light are red, green and blue; Pigments are magenta, yellow and cyan.

14 infrared 1 strong thermal effect; 2. Strong ability to penetrate clouds; Ultraviolet rays can help the human body synthesize vitamin D, kill microorganisms and make fluorescent substances glow.

15 sunlight is an important source of natural ultraviolet rays, and excessive ultraviolet rays do great harm to human body.

1. Linear propagation of light: Light propagates linearly in the same homogeneous medium. Aperture imaging, shadow and spot are all linear propagation phenomena of light.

The maximum speed of light in vacuum is 3x108m/s = 3x105km/s.

Law of light reflection: one side, two sides and three dimensions. The angle between the incident light and the normal is the incident angle. The angle between the reflected light and the normal is the reflection angle.

Imaging characteristics of plane mirror: virtual image, equal size, equal distance and mirror symmetry. The reflection of objects in water is the reflection of virtual images and light.

3. The phenomenon and law of light refraction: Seeing the virtual image of chopsticks and fish in water is the phenomenon of light refraction.

Convex lens has the function of converging light, while concave lens has the function of diverging light. The law of refraction of light: one side, two sides, three sides, big four empty.

3. The law of convex lens imaging: [When u = f, no imaging; When U=2f, V=2f becomes a real image with inverted size]

Properties of object distance U image distance V image Application of light path diagram

U & gt2f f<v & lt2f Inverted Micro Reality Camera

F<u & lt2f v & gt2f Inverted Amplification Real Slide Projector

U< magnifying glass

⒌ Convex lens imaging experiment: Put the candle, convex lens and light screen on the optical bench in turn, so that the centers of the candle flame, convex lens and light screen are at the same height.