Question

F1=8HL2=40cмF2=1HL1=? ​

Answer 1

по св-ву пропорции.

1×40÷8=5

Answer 2

To find the value of L1, we can use the formula for the focal length of a lens:

$\frac{1}{F_1} + \frac{1}{F_2} = \frac{1}{L_1}$

Given that F1 = 8H and F2 = 40 cm, we can substitute these values into the formula:

$\frac{1}{8H} + \frac{1}{40 \, \text{cm}} = \frac{1}{L_1}$

Now, we need to convert the units so that they are consistent. Let's convert 40 cm to H:

40 cm = 0.4H

Substituting this value into the equation:

$\frac{1}{8H} + \frac{1}{0.4H} = \frac{1}{L_1}$

Simplifying the equation further:

$\frac{1}{8H} + \frac{1}{0.4H} = \frac{1}{L_1}$

$\frac{1}{8} + \frac{1}{0.4} = \frac{1}{L_1}$

$\frac{0.4 + 8}{8} = \frac{1}{L_1}$

$\frac{8.4}{8} = \frac{1}{L_1}$

$1.05 = \frac{1}{L_1}$

To find L1, we can take the reciprocal of both sides of the equation:

$\frac{1}{1.05} = L_1$

$L_1 = \frac{1}{1.05}$

$L_1 \approx 0.952$ H

Therefore, the value of L1 is approximately 0.952H.