Question

A camera lens focuses light from a 12.0 m
tall building located 35.0 m away on film
50.0 mm behind the lens. How tall is the
image of the building on the film ?
1) 7.00 mm
2) 17.1 mm
3) 1.25 mm
4) 2.51 mm​

Answer 1

Answer:

The answer is 17.1 mm whereby,

O=12cm , u=-35cm v=50 and we have to find I=

Answer 2

Given: A camera lens focuses light from a 12 m tall building located 35 m away film at 50mm behind the lens

To find: Length of the image of the building on the film

Explanation: Let magnification of the lens be m.

Image distance(v)= 50 mm

= 0.05 m

Object distance (u) = 35 m

The formula for magnification in lens is as follows:

m = v / u

= 0.05/35

The magnification formula relating the length of the object and image is:

m= height of image / height of object

=> 0.05/35= height of image / 12

=> height of image= 12 * 0.05 / 35

= 0.0171 m

= 17.1 mm ( 1 m= 1000 mm)

Therefore, the length of the image of the building on the film is option (b) 17.1 mm.