A camera has a lens with a focal length of 60 mm.Suppose you replace the normal lens with a zoom lens whose focal length can be varied from 35 mm to 250 mm.and use the camera to photograph an object at infinity.Compared to a 60 mm lens,what magnification of the image would be achieved using the 240 mm focal length?
A)2-times
B)4-times
C)8-times
D)16-times

Question

Quizplus · Accepted Answer

The magnification of an image is given by the formula M = -d_i/d_o, where d_i is the image distance and d_o is the object distance. When the object distance is at infinity (as in the given scenario), then d_o = ∞, which simplifies the formula to M = -d_i / ∞ = 0.
The magnification achieved with a 60 mm lens is therefore 0, regardless of the object distance.
With the zoom lens set to 240 mm focal length, the magnification would be:
M = -d_i / ∞ = 0 for the object distance. 
The magnification is independent of the focal length in this case, so the answer is 0 times the magnification achieved with the 60 mm lens.
Therefore, the magnification achieved with a 240 mm focal length is 0 x magnification achieved with a 60 mm lens, which equals 0. 
To find how many times smaller the magnification with the zoom lens is than the magnification with the 60 mm lens, we need to take the ratio: 0 / 0 = undefined (since we cannot divide by 0). Therefore, the correct answer is not listed as an option, and the question is flawed.

A Camera Has a Lens with a Focal Length of 60