Question

How far from a piece of paper must you hold your father’s 2.25 D reading glasses to try to burn a hole in the paper with sunlight?

a) 0.44 m

b) 0.89 m

c) 1.33 m

d) 2.00 m

Answer 1

To focus sunlight and burn a hole in a piece of paper using 2.25 D reading glasses, they should be held approximately 0.44 meters away from the paper, which is the glasses' focal length calculated by taking the inverse of their power in diopters. Option a is the correct answer.

Step-by-step explanation:

The student question asks how far from a piece of paper must you hold your father's 2.25 D reading glasses to try to burn a hole in the paper with sunlight. This problem involves understanding the concept of lens focal length and its relation to lens power in diopters (D). The power of a lens (in diopters) is the inverse of the focal length (in meters). Therefore, to find the focal length (f), we use the formula f = 1/P, with P being the power of the lens in diopters.

To find the focal length for the 2.25 D reading glasses, we would calculate:

Convert the diopters to the focal length using the formula: f = 1/P.

For 2.25 D glasses, the focal length is f = 1/2.25 D = 0.444 m.

To effectively focus sunlight and burn a hole in the paper, the glasses should be held at the focal length from the paper. Therefore, you would hold the glasses approximately 0.44 meters from the paper. This corresponds to answer choice (a).