Question

You are provided with four lenses of focal lengths 1cm, 3cm, 10cm, and 100 cm. Which two would you prefer for a microscope and which two for a telescope?

a. 1cm and 3cm for microscope, 10cm and 100cm for telescope
b. 1cm and 10cm for microscope, 3cm and 100cm for telescope
c. 1cm and 100cm for microscope, 3cm and 10cm for telescope
d. 3cm and 10cm for microscope, 1cm and 100cm for telescope

Answer 1

For microscopes, lenses with short focal lengths are chosen for higher magnification, hence 1cm and 3cm lenses are preferred. For telescopes, a long focal length objective gathers more light from distant objects, making 1cm and 100cm lenses suitable for the eyepiece and objective respectively.

Step-by-step explanation:

For constructing a microscope, lenses with relatively short focal lengths are preferred because they provide higher magnification. In this case, the lenses with focal lengths of 1cm and 3cm would be ideal, with the 1cm lens serving as the eyepiece and the 3cm lens as the objective. The objective lens (closer to the object) requires a shorter focal length to provide a greater magnification of the object, whereas the eyepiece (closer to the eye) further magnifies the intermediate image.

For constructing a telescope, a lens with a much longer focal length is used as the objective to collect more light from distant objects and provide a clear image. The lens with the 100cm focal length would serve as the objective, and the lens with the 1cm focal length would be the eyepiece. The objective lens in a telescope is focused on distant objects, producing a smaller, but bright and clear image, and the eyepiece lens then magnifies this image for the observer's vision.