What are the characteristics of concave-convex mirror? What are the applications?

1, the reflection phenomenon on the concave-convex mirror obeys the law of light reflection.

2. After the light parallel to the principal axis is reflected by concave mirror, the reflected light converges to the focal point. The focus of the concave-convex mirror is the convergence point of the actual light, so it is the real focus.

3. Concave-convex mirror can focus light, so the smaller the focal length, the greater the focusing ability.

Application:

1, using concave-convex mirror to concentrate light: solar cooker, desk lamp, TV satellite antenna, radar.

2. The light passing through the focus is reflected into parallel light parallel to the main shaft: searchlights, flashlights and headlight lampshades of various motor vehicles.

The geometric drawing of concave lens imaging is the same as that of convex lens. From the top of the object, it is also regarded as two straight lines: one parallel to the main optical axis, deflected into divergent light after passing through the concave lens, and returned to the main focus in the opposite direction; The other line passes through the optical center of the lens, and these two straight lines intersect at one point, which is the image of the object.

Extended data:

The image formed by concave lens is always smaller than the vertical virtual image of the object, and concave lens is mainly used to correct myopia. Myopia is mainly due to lens deformation, which leads to premature light gathering in front of the retina. The concave lens plays the role of diverging light. The concave lens forms an upright and reduced virtual image, which lengthens the image distance and falls right on the retina.

When an object is a real thing, it becomes an upright and reduced virtual image, and the image and the object are on the same side of the lens.

When the object is a virtual object, the distance from the concave lens to the virtual object is twice the focal length (referring to the absolute value u

When the object is a virtual object and the distance from the concave lens to the virtual object is twice the focal length (absolute value u=f), the image is imaged at infinity.

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