Physics · Reflection of light, spherical mirrors, mirror formula

A spherical mirror and a thin spherical lens have each a focal length of The mir

A spherical mirror and a thin spherical lens have each a focal length of \( -15 \mathrm{cm} \) The mirror and lens are likely to be:

  • A. both concave
  • B. both Convex
  • C. the mirror is concave and lens is convex
  • D. the mirror is convex but lens is concave

Step-by-step solution

For spherical mirrors, concave mirrors have negative focal length (according to Cartesian sign convention), while convex mirrors have positive focal length. For thin spherical lenses, convex lenses have positive focal length, and concave lenses have negative focal length. Given that both have focal length -15 cm, the mirror is concave and the lens is concave.
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