Which lens has a virtual focus?a)Concave lensb)Convex lensc)Converging...
Concave lenses are thinner at the middle. Rays of light that pass through the lens are spread out (they diverge). A concave lens is a diverging lens. When parallel rays of light pass through a concave lens the refracted rays diverge so that they appear to come from one point called the principal focus.
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Which lens has a virtual focus?a)Concave lensb)Convex lensc)Converging...
Concave Lens: A Lens with a Virtual Focus
Introduction:
A lens is a transparent material that is bound by two curved surfaces or one curved and one plane surface. Lenses are classified into two main types: convex lenses and concave lenses. Convex lenses are thicker at the center and thinner at the edges, while concave lenses are thinner at the center and thicker at the edges.
Virtual Focus:
The virtual focus of a lens is the point where the extended rays of light appear to meet after passing through the lens. In the case of a concave lens, the virtual focus is formed on the same side of the lens from where the incident rays of light approach. This is in contrast to a convex lens, where the virtual focus is formed on the opposite side of the lens from where the incident rays approach.
Explanation:
When light rays pass through a concave lens, they diverge or spread out. This divergence of light rays continues even after they pass through the lens. As a result, the extended rays of light appear to meet at a point on the same side of the lens as the source of light. This point is known as the virtual focus.
Characteristics of a Concave Lens:
1. Diverging: Concave lenses are diverging lenses as they cause the incident rays of light to spread out.
2. Thin Center: Concave lenses are thinner at the center and thicker at the edges.
3. Negative Focal Length: The focal length of a concave lens is negative, indicating that the virtual focus is formed on the same side of the lens as the source of light.
4. Reduces Image Size: When an object is viewed through a concave lens, the image formed is smaller than the actual object.
Conclusion:
In summary, a concave lens has a virtual focus. This is because the lens causes the incident rays of light to spread out, resulting in the extended rays appearing to meet at a point on the same side of the lens as the source of light. This virtual focus is one of the distinguishing characteristics of a concave lens.
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