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According to the New Cartesian Sign Convention, which one of the following is correct in respect of the formula 1 f = 1 v + 1 u , where symbols have their usual meanings?

Options

  1. AIt applies only to spherical mirrors.
  2. BIt applies only to spherical lenses.
  3. CIt applies to spherical mirrors as well as spherical lenses.
  4. DIt is an invalid formula.

Correct answer

A. It applies only to spherical mirrors.

Step-by-step solution

The formula is a relation between the object distance u , image distance v and the focal length from the pole of the mirror. The formula is valid for the images in spherical mirror. In lenses, there comes minus in place of addition. Mirro formula, 1 v + 1 u = 1 f and Lens formula, 1 v - 1 u = 1 f

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