Question

the length of a pin-hole camera is 12cm, it is used to photograph an object 60cm away and 80 cm hight, calculate the height of the image and the magnification produced

Answer 1

Convex lenses are used in the camera.

Given that, the length of a pin-hole camera is 12cm, it is used to photograph an object 60cm away and 80 cm height.

From above data we have, image distance from the camera is 12 cm, object distance is 60 cm and height of object is 80 cm.

We have to find the height of the image and the magnification produced.

m = v/u = hi/ho

Here, m = magnification, v = image distance from mirror, u = object distance, hi = height of image and ho = height of object.

m = v/u

Substitute the known values,

m = 12/60

m = 1/5

m = 0.2

Therefore, the magnification is 0.2.

Also,

m = hi/ho

Substitute the values,

0.2 = hi/80

0.2*80 = hi

16 = hi

Therefore, the height of the image is 16 cm.