Which of the following represents the relationship between the radius of curvature (R) and focal length (f), of a spherical mirror?

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  1. f = 2/R
  2. R = 2f 
  3. f = 2R
  4. R = 2/f 

Answer (Detailed Solution Below)

Option 2 : R = 2f 
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Detailed Solution

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The correct answer is R = 2f.

Key Points

  • The relationship between the radius of curvature (R) and focal length (f) of a spherical mirror is given by the equation R = 2f.
  • This means that the radius of curvature is twice the focal length of the mirror.
  • This relationship holds true for both concave and convex mirrors.
  • The focal length (f) is the distance from the mirror to the focal point, where parallel rays of light converge (concave) or appear to diverge from (convex).

Additional Information

  • Types of Spherical Mirrors:
    • Concave Mirror: A mirror with a surface that curves inward like the inside of a sphere. It converges light rays to a focal point.
    • Convex Mirror: A mirror with a surface that curves outward. It diverges light rays, making them appear to come from a focal point behind the mirror.
  • Principal Axis: The straight line perpendicular to the surface of the mirror that passes through its center and the focal point.
  • Focal Point (F): The point where parallel rays of light either converge (in concave mirrors) or appear to diverge from (in convex mirrors) after reflecting off the mirror.
  • Mirror Equation: The mirror equation relates object distance (u), image distance (v), and focal length (f) and is given by 1/f = 1/u + 1/v.
  • Applications: Spherical mirrors are used in various applications like telescopes (concave), rear-view mirrors in vehicles (convex), and shaving mirrors (concave).
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