Question

The unit of magnification is:
(A) $m$
(B) ${m^2}$
(C) ${m^{ - 1}}$
(D) None of these

Answer 1

Hint Magnification is the ratio of the height of the image to the height of the object it shows how strongly an optical instrument can magnify the image of an object. By magnify, we mean both to enlarge and diminish the size of the object.

Formula used
$m = \dfrac{{{h_i}}}{{{h_o}}}$
Where $m$ is the magnification, ${h_i}$ is the height of the image, and ${h_o}$ is the height of the object.

Complete Step-by-step solution
We know that magnification is the ratio of the height of the image to the height of the object.
$\Rightarrow m = \dfrac{{{h_i}}}{{{h_o}}}$
Where $m$ is the magnification, ${h_i}$is the height of the image, and ${h_o}$is the height of the object.
Hence magnification will be a dimensionless quantity as it is the ratio of quantities with the same dimensional formula.

Hence the correct answer to the above question is (D) None of these

Additional information
For mirror magnification is also defined as the negative of the ratio of image distance to the object distance and calculations are made based on sign convention.
$\Rightarrow m = - \dfrac{v}{u}$
Where $m$ is the magnification, $v$ is the distance of the image, and $u$ is the distance of the object.
For lens magnification is also defined as the ratio of image distance to the object distance and calculations are made based on sign convention.
$\Rightarrow m = \dfrac{v}{u}$
Where $m$ is the magnification, $v$ is the distance of the image, and $u$ is the distance of the object.

Note
Some common uses of lens magnification are a microscope, telescope, magnifying glass, and a projector. Commonly we use a lens of magnification enough to magnify an object’s image without distorting it. By magnifying an object’s image we are not making a change to the real object.