Question

A concave mirror is used to focus the image of a flower on a nearby well 120cm from the flower. If a lateral magnification of 16 is desired, the distance of the flower from the mirror should be

• A. 8 cm
• B. 12 cm
• C. 80 cm
• D. 120 cm

Answer 1

The correct option is (D) 8 cm

Step 1, Given data

Magnification = 16

Step 2, Finding the object's distance

We know,

magnification =$\frac{v}{u}=16$

And also

$v=u+120$

Now, putting the value of v

We get,

$\therefore \frac{120+u}{u}=16\Rightarrow 15u=120\Rightarrow u=8cm.$

Hence the object distance is 8 cm