Convex mirror, and you point a light at it horizontally

In summary, when a convex mirror is used and a light is pointed at it horizontally, the light will always reflect through the focal point. This is only true when the size of the mirror is small compared to the radius of curvature. If the mirror is semi-circular, the behavior will be different and glancing is not a violation, as it is outside the domain where the rule applies.
  • #1
Alkatran
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If you have a convex mirror, and you point a light at it horizontally, does the light always reflect through the focal point? (the point halfway on the line connecting border and the center, parallel to the light's initial path)

I remember learning this, but I think of a mirror in the shape of a semi-circle, and you point the light at the bottom, it only bounces along the edge...?
 
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  • #2
Horizontal (parallel to the axis) rays will reflect from a convex mirror so that they appear to originate from the focal point.
 
  • #3
Also, this is only true in the limiting case when the size of the mirror (aperture) is small compared to the radius of curvature. So, when you take a semi-circular (actually hemispherical) mirror, it is no longer small compared to R. So, the behavior will be different, and hence glancing is not a violation. It's just outside the domain that the above rule applies to.
 

1. How does a convex mirror reflect light?

A convex mirror reflects light by curving outwards, which causes parallel light rays to diverge and reflect off the surface.

2. What is the difference between a convex and concave mirror?

A convex mirror curves outwards and reflects light outwards, while a concave mirror curves inwards and reflects light inwards.

3. What happens to the size of an object in front of a convex mirror?

An object in front of a convex mirror appears smaller than its actual size due to the diverging nature of the reflected light rays.

4. How does the distance of an object from a convex mirror affect its image?

The closer an object is to a convex mirror, the smaller its image will appear. As the object moves farther away, the image will appear larger.

5. What are some real-life applications of convex mirrors?

Convex mirrors are commonly used as side-view mirrors on vehicles to provide a wider field of vision. They are also used in security cameras, road safety mirrors, and makeup mirrors.

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