Question

От флакончика до собирающей линзы расстояние d=30см,а от его действительного изображения до линзы расстояние f=60см.Определите фокусное расстояние линзы.

Answer 1

1/F = 1/f+1/d
1/F = 1/60cм+1/30cм
1/F=1/60+2/60
1/F=3/60=1/20см
F=20см
Ответ: 20см

Answer 2

Calculation of the focal length of the lens

To determine the focal length of the lens, we can use the lens formula:

`1/f = 1/d_o + 1/d_i`

Where: - `f` is the focal length of the lens - `d_o` is the object distance (distance from the object to the lens) - `d_i` is the image distance (distance from the image to the lens)

In this case, we are given: - `d_o = 30 cm` (distance from the object to the lens) - `d_i = 60 cm` (distance from the image to the lens)

Substituting these values into the lens formula, we can solve for `f`:

`1/f = 1/30 + 1/60`

To simplify the equation, we can find a common denominator:

`1/f = (2 + 1)/60`

`1/f = 3/60`

`1/f = 1/20`

Therefore, the focal length of the lens is 20 cm.