Question

A farsighted man cannot focus clearly on objects that are less than 145 cm from his eyes. To correct this problem, he wears eyeglasses that are located 2.0 cm in front of his eyes. Determine the focal length that will permit him to read The Gleaner, keeping it 32.0 cm from his eyes.

Answer 1

1.212447π

Step-by-step explanation:

To determine the focal length we use the formula

1/f=1/v-1/u
Here U is 145 cmand v is 32cm

therefore we use pythagorus theorem

AC^2=AB^2+BC^2

then we use reciprocal of circle

=1.212447π (use 3.14 or 22/7)

Answer 2

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

1/f = 1/do + 1/di

where f is the focal length of the lens, do is the object distance (the distance from the object to the lens), and di is the image distance (the distance from the lens to the image).

In this case, the object distance is 32.0 cm (the distance from the man's eyes to the book), and the image distance is the distance from the lens to the man's eyes, which is 2.0 cm. We want to find the focal length, so we can rearrange the equation to solve for f:

1/f = 1/do + 1/di

1/f = 1/32.0 cm + 1/2.0 cm

1/f = 0.03125 cm^-1 + 0.5 cm^-1

1/f = 0.53125 cm^-1

f = 1.881 cm

Therefore, the required focal length of the corrective lenses is approximately 1.881 cm.