According to the New Cartesian Sign Convention, which one of the follo

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

Download PDF Attempt Online

The formula $\frac{1}{f} = \frac{1}{v} + \frac{1}{u}$ is the standard equation that applies to both spherical mirrors and spherical lenses when used with the New Cartesian Sign Convention.

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.

While the formula form is the same, the application of the sign convention and the meaning of $f$ (positive for converging, negative for diverging) correctly distinguish between types of mirrors and lenses. Other related formulas, like the magnification formula ($m = \frac{h’}{h} = -\frac{v}{u}$ for mirrors and $m = \frac{h’}{h} = \frac{v}{u}$ for lenses, with the sign convention applied), are also used in conjunction with these fundamental formulas.

Join Our Telegram Channel

More similar MCQ questions for Exam preparation:-