According to the New Cartesian Sign Convention, which one of the following is correct in respect of the formula $\frac{1}{f} = \frac{1}{v} + \frac{1}{u}$, where symbols have their usual meanings?
It applies only to spherical mirrors.
It applies only to spherical lenses.
It applies to spherical mirrors as well as spherical lenses.
It is an invalid formula.
Answer is Right!
Answer is Wrong!
This question was previously asked in
UPSC NDA-1 – 2021
For spherical mirrors, this is known as the mirror formula. For spherical lenses, it is known as the thin lens formula. The New Cartesian Sign Convention provides a consistent set of rules for assigning positive or negative signs to object distance ($u$), image distance ($v$), and focal length ($f$), ensuring that the formula holds true for both real and virtual images/objects and for both converging and diverging mirrors/lenses.