Question

A concave mirror forms an erect image of an object placed at a distance of 10 cm from it. The size of the image is double that of the object. Where is the image formed?

• A. 20 cm behind the mirror
• B. 20 cm in front of the mirror
• C. 40 cm behind the mirror
• D. 40 cm in front of the mirror

Answer 1

The correct option is A 20 cm behind the mirror

Since the image is erect , so the magnification ratio must be positive .

$m=2$

also $u=-10cm$

so $m=-\frac{v}{u}$

$2=-\frac{v}{-10}$

$v=20cm$

So the image is virtual and 20 cm from mirror on the other side of the object.