Question

An object is placed at a distance of 12 cm in front of a concave mirror. It forms a real image four times larger than the object. Calculate the distance of the image from the mirror.

Answer 1

 Image height, object height, image distance, and object distance are related as: It is given that: h` = 4h u = −12 cm v = 12 × 4 = 48 cm Therefore, the image distance is 48 cm behind the mirror.

Answer 2

Given:

• Object is placed in front of concave mirror at a distance of 12 cm.

• It forms a real image 4x larger than object.

To find:

• Distance of image from mirror.

Answer:

• The distance of image from Mirror is 48 cm.

Explanation:

By using formula of Magnification,

Height of Image/Height of Object = -V/U

U = -12    (∵ Negative because, The object is real.)

Height of image/Height of object:

      ⇒ 4/1

      ⇒ -V/-12 = 4/1

      ⇒ 12 × 4

      ⇒ 48 cm

Therefore, Distance of image from mirror is 48 cm.