Determine the magnification given by a lens with a focus distance of 0.13m, if the object is 15cm behind it.

Let a lens be given, the focal length of which is F = 0.13 m.It is known from the problem statement that the object is at a distance of d = 15 cm = 0.15 m from it

Since the magnification G given by the lens is found as the ratio of the distance from the lens to the image of the object – f to the distance from the lens to the object d, it is necessary to first determine f from the formula for a thin lens. We get:

1 / F = 1 / d + 1 / f;

f = d F / (d – F).

Let’s combine the formulas: Г = f / d;

Г = d · F / (d – F): d;

Г = F / (d – F).

Let’s substitute the values ​​of physical quantities into the calculation formula and make calculations: Г = 0.13 m / (0.15 m – 0.13 m); G = 6.5.

Answer: The magnification given by the lens is 6.5 times.