If I had the old-fashion camera that had a focal length of 35mm(0.035m) and I take a picture of a person 6 m away, how far does the film need to be from the lens to record a clear image?
I know that the equation is 1/f = 1/d(object) + 1/d(image) so would I do the following:
1/0.035m = 1/6 +1/unknown
28.57 = .1666+ 1/unknown
28.57-.1666=28.40
di=1/28.40 = .035m
Is this even close or all wrong-it doesn't sound correct
I just reposted becuase the above doesn't say Physics for Subject
This looks right to me.
3.5cm is about 1.4 inches which is about the depth you would expect for such a camera.
Thank you-I really appreciate you checking it
You are on the right track using the lens formula, but there seems to be a slight mistake in your calculations. Let me guide you step by step through the correct calculation.
The lens formula you mentioned is correct:
1/f = 1/d(object) + 1/d(image)
In this case, the focal length (f) of the lens is given as 35mm (0.035m), and the object distance (d(object)) is 6m.
Now, let's substitute the values in the equation:
1/0.035m = 1/6m + 1/d(image)
To simplify the equation, let's find the common denominator:
1/0.035m = (6 + 1/d(image))/6m
Now, cross multiply:
6m * 1/0.035m = 6 + 1/d(image)
Simplifying further:
171.43 = 6 + 1/d(image)
Rearranging the equation to solve for 1/d(image):
1/d(image) = 171.43 - 6
1/d(image) = 165.43
Now, taking the reciprocal to calculate d(image):
d(image) = 1/(165.43)
d(image) ≈ 0.006m (rounded to three decimal places)
Therefore, the distance from the film to the lens to record a clear image is approximately 0.006m or 6mm.
So, your calculation was quite close, but there was a small error in the final step. Double-checking your calculations and rounding properly, the correct answer is around 6mm.