Question

If the object distance in the following picture were 8.0 m and the image distance were 2.0 m, what is the focal length?

a) 1.0 m
b) 4.0 m
c) 1.6 m
d) 0.63 m

Answer 1

The focal length of a lens, given an object distance of 8.0 m and an image distance of 2.0 m, is calculated to be 1.6 m, which is option c).

Step-by-step explanation:

To find the focal length of a lens, we can use the lens formula which relates the object distance (o), the image distance (i), and the focal length (f):
1/f = 1/o + 1/i.

Given that the object distance is 8.0 m and the image distance is 2.0 m, we can substitute these values into the formula:

1/f = 1/8.0 m + 1/2.0 m
1/f = 0.125 m-1 + 0.5 m-1
1/f = 0.625 m-1

Now, to find the focal length, we take the reciprocal of the result:

f = 1/0.625 m-1
f = 1.6 m

Hence, the focal length of the lens is 1.6 m, which corresponds to option c).