The minimum number of rays required to locate the image formed by a spherical mirror is _____.
- AOption (a)
One
- BOption (b)
Two
- COption (c)
Three
- DOption (d)
Four
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Correct answer
Two
Why this answer is correct
The correct answer is Two.
Key Points
- Spherical mirrors are curved mirrors with a spherical surface, either concave or convex, used to reflect light.
- To locate the image formed by a spherical mirror, at least two rays are required to determine the position and characteristics of the image.
- The first ray is typically drawn parallel to the principal axis and reflects through the focus of the mirror.
- The second ray is drawn passing through the focus (in case of concave mirrors) or appearing to pass through the focus (in case of convex mirrors) and reflects parallel to the principal axis.
- These two reflected rays intersect (or appear to intersect) at a point, which provides the location of the image.
Additional Information
- Types of spherical mirrors:
- Concave mirrors: These mirrors have an inward curved surface and are used to focus light. They can form real and virtual images depending on the position of the object.
- Convex mirrors: These mirrors have an outward curved surface and always form virtual, upright, and diminished images.
- Principal axis: It is an imaginary line passing through the center of curvature and the pole of the spherical mirror.
- Focus: The point on the principal axis where rays parallel to the principal axis converge (concave mirror) or appear to diverge from (convex mirror) after reflection.
- Image formation rules:
- Ray parallel to the principal axis reflects through the focus.
- Ray passing through the focus reflects parallel to the principal axis.
- Ray passing through the center of curvature reflects back along the same path.
- Applications: Spherical mirrors are used in telescopes, headlights, shaving mirrors, and rear-view mirrors in vehicles.
Important Points
- Ray diagrams: Ray diagrams are essential tools for understanding image formation by spherical mirrors. They use two or more rays to determine the image's position, size, orientation, and type.
- Real vs. Virtual images:
- Real images: Formed when reflected rays converge and can be projected on a screen.
- Virtual images: Formed when reflected rays appear to diverge from a point and cannot be projected on a screen.
- Mirror formula: The relationship between object distance (u), image distance (v), and focal length (f) is given by 1/f = 1/v + 1/u.
- Magnification: Magnification (M) is the ratio of the height of the image to the height of the object and is given by M = -v/u.
- Center of curvature: The center of the spherical surface of which the mirror forms a part. It is denoted by C.