Question

If an object of 7 cm height is placed at a distance of 12 cm from a convex lens of focal length 8 cm, find the position, nature and height of the image​

Answer 1

If an object of 7 cm height is placed at a distance of 12 cm from a convex lens of focal length 8 cm, find the position, nature and height of the image. ... Thus, the height or size of hte image is 14 cm.

Answer 2

Explanation:

We have given,

Object height, h = 7cm

Object distance, u = -12cm

Focal length, f = 8cm

Let height of image be H cm.

By using lens formula,

1/f = 1/v - 1/u

1/8 = 1/v - (-1/12)

1/v = 1/8 - 1/12

1/v = 6-4/48....(Taking LCM and then cross multiplication)

1/v = 2/48

v = 24 cm

So, image distance(position) is 24cm.

Now, We have to find magnification,

So, M = v/u

M = 24/-12

M = -2

Similarly we can find height of image,

So, M = H/h

-2 = H/7

H = -14cm

So, image height is -14cm which means it is inverted bcoz it has negative sign.

Therefore, Image formed is real and inverted.