21. Positioning of Lenses in a Compound
Microscope
โข A compound microscope has two types of
lenses. It has objective lenses and an ocular
lens.
โข The objective lenses are located in the
rotating nosepiece, near the object being
magnified.
โข The ocular lens is located in
the part you look through,
which magnifies the image.
Objective Lens
Ocular Lens
22. Positioning of Lenses in a Telescope
โข A telescope has two lenses: an objective lens and an
eyepiece lens.
โข The objective lens is located at the end of the
telescope, and it collects light from a distance and
then it brings that image into focus.
โ The eyepiece lens takes that
focus and magnifies it to make
the image or object look bigger
to the retina.
23. Eyeglasses vs. Contact Lenses
โข Eyeglasses are a frame that holds two pieces of glass
or plastic, which have been ground into lenses to
correct refractive errors
โข Contact lenses are worn directly on the cornea of the
eye
โข Eyeglasses and Contacts help with sight by adding or
subtracting focusing power to the eyeโs cornea and lens
