Question

If the magnification of a body of size $1\,m$ is $2$, what is the size of the image?
A. $1\,m$
B. $2\,m$
C. $3\,m$
D. $4\,m$

Answer 1

Hint:In this problem size of the object is given and the magnification is also given to us so using the magnification formula that is size of the image divided by the size of the object equals the magnification we can find out the value of the size of the image.

Formula used:
$M = \dfrac{{{h_2}}}{{{h_1}}}$
Where, $M = $ Magnification, ${h_2} = $ Size of the image and ${h_1} = $ Size of the object.

Complete step by step answer:
As given in the question, the size of the object is equal to $1m$. Where the SI unit of the size of the object is measured in terms of meter. Size of the image is not given in the problem which we have to calculate using the magnification formula.The magnification formula stats the ratio of of the size of image to the size of object which is mathematically represented as,
$M = \dfrac{{{h_2}}}{{{h_1}}}$
And in the problem it is given that,
Magnification$ = 2$
Putting all the given values in the magnification formula we gwt,
$2 = \dfrac{{{h_2}}}{{1m}}$
Rearranging the above equation we will get,
${h_2} = 2 \times 1m$
$ \therefore {h_2} = 2\,m$
As the SI unit of size of image is measured in terms of meter.

Therefore the correct option is B.

Note:The unit of the magnification is unitless as it is measured by the ratio and all the rational terms are unitless. This is a simple problem but you have to remember different magnification formulas according to the problem and you have to use different formulas.