Physics · Reflection of light, spherical mirrors, mirror formula

A convex mirror of radius of curvature forms an image which is half the size of

A convex mirror of radius of curvature \( 20 \mathrm{cm} \) forms an image which is half the size of the object.How far is the object from the mirror?

  • A. \( 5 \mathrm{cm} \)
  • B. 7.5 \( \mathrm{cm} \)
  • C. -30 \mathrm{cm} \)
  • D. 12.5 cm

Step-by-step solution

For a concave mirror, focal length f = R/2 = -10 cm (using sign convention). Given magnification m = -1/2 (real and inverted), using mirror formula 1/f = 1/u + 1/v and m = -v/u, we get u = -30 cm. The object is 30 cm from the mirror, with negative sign indicating it is in front. The problem likely intends a concave mirror.
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