Shortcut Methods

1 : Mirror Formula Shortcut#

• When dealing with spherical mirrors (concave or convex), you can use the mirror formula: $$(\frac{1}{f} = \frac{1}{v} + \frac{1}{u}),$$ where (f) is the focal length, (v) is the image distance, and (u) is the object distance. For quick calculations, if you know the nature of the mirror (concave or convex), you can determine the sign of $f$ and $u$ based on their position relative to the mirror. This simplifies the formula: For concave mirrors: $f$ is positive and $u$ is negative.
  • For convex mirrors: (f) is negative, and (u) is positive.