Question

Фокусное расстояние собирающей линзы 20 см. на какое расстояние от линзы следует поместить предмет, чтобы его изображение было в натуральную величину?

Answer 1

Предмет должен находиться в фокусе линзы, т.е. на расстоянии 20 см

Answer 2

Calculation of the Distance for a Natural Size Image

To determine the distance at which an object should be placed from a converging lens in order to obtain a natural size image, we can use the lens formula:

1/f = 1/v - 1/u

Where: - f is the focal length of the lens - v is the image distance (distance of the image from the lens) - u is the object distance (distance of the object from the lens)

In this case, the focal length of the converging lens is given as 20 cm. We need to find the object distance (u) at which the image will be of natural size.

To find the object distance, we can rearrange the lens formula as follows:

1/u = 1/f - 1/v

Since we want the image to be of natural size, the magnification (m) should be equal to 1. The magnification is given by:

m = -v/u

For a natural size image, m = 1. Therefore, we can rewrite the magnification equation as:

1 = -v/u

Now, substituting the values into the equation:

1/u = 1/20 - 1/v

Since we want the image to be of natural size, we can substitute 1 for v/u:

1 = 1/20 - 1/v

Simplifying the equation:

1/v = 1 - 1/20

**1/v =