Microscopes and telescopes both consist of two converging lenses cont.pdf

Microscopes and telescopes both consist of two converging lenses contained in a tube. What is
the difference in set-up of the two lenses between a microscope and a telescope? The rearview
mirror on a truck warns the user that objects may be closer than they appear. What kind of mirror
is being used, and why was that type selected? Why does a clear stream always appear to be
shallower than it actually is? Discuss the type of aberration involved in each of the following
situations. (i) The edges of the image appear reddish. (ii) The image cannot be clearly focused.
A baby fish has his eyesight tested and is found to be myopic. His father wants to make a set of
glasses to correct for this problem. Since fish live under water, the father fish will make the
glasses out of a very thin clear plastic bag which is filled with air (n = 1.000). What type of lens
does the fish need to make? What shape should the lens be? What is the wavelength of yellow
light?
Solution
In refracting telescopes, there are typically two convex lenses. One lens acts as the objective
lens: this lens gathers light from faraway objects and forms a real, inverted image of the object at
its focal point. A second lens, called the eyepiece, is positioned such that the image formed by
the objective lens is at its focal point. When an observer looks through the eyepiece with a
relaxed eye, they are able to see an object of the image, formed at infinity. Microscopes are used
to look at magnified images of small objects. A simple microscope (a “magnifying glass”)
consists of a single convex lens. The lens is held close to the object so that the object is between
the lens and its focal point. When viewed from the other side of the lens, a magnified, virtual,
upright image is seen. The compound microscope is the most common type of microscope used
in laboratories. With these microscopes, an objective lens is used to create an inverted, real
image of the object. Using the eyepiece, the image is magnified. In this sense, its operating
principles are similar to that of a refracting telescope. The rear view mirror is a convex mirror
which forms a virtual and erect image of the object which is smaller in length than the object.
Because the image formed is smaller in length, it appears to be farther away and hence, the
warning written on it. This is because of the phenomenon of refraction of light as it crosses the
medium of water(refractive index greater than that of air). As the light ray travels from
water(denser medium) to air(rarer medium), the light ray bends away from the normal and the
image of the bottom of the stream seems to be raised and hence, the stream appears to be
shallower. a) In optics, chromatic aberration (CA, also called chromatic distortion, and
spherochromatism) is an effect resulting from dispersion in which there is a failure of a lens to
focus all colors to the same convergence point. It occurs because lenses have different refractive
indices for differentwavelength.

1. Microscopes and telescopes both consist of two converging lenses contained in a tube. What is
the difference in set-up of the two lenses between a microscope and a telescope? The rearview
mirror on a truck warns the user that objects may be closer than they appear. What kind of mirror
is being used, and why was that type selected? Why does a clear stream always appear to be
shallower than it actually is? Discuss the type of aberration involved in each of the following
situations. (i) The edges of the image appear reddish. (ii) The image cannot be clearly focused.
A baby fish has his eyesight tested and is found to be myopic. His father wants to make a set of
glasses to correct for this problem. Since fish live under water, the father fish will make the
glasses out of a very thin clear plastic bag which is filled with air (n = 1.000). What type of lens
does the fish need to make? What shape should the lens be? What is the wavelength of yellow
light?

Solution
In refracting telescopes, there are typically two convex lenses. One lens acts as the objective
lens: this lens gathers light from faraway objects and forms a real, inverted image of the object at
its focal point. A second lens, called the eyepiece, is positioned such that the image formed by
the objective lens is at its focal point. When an observer looks through the eyepiece with a
relaxed eye, they are able to see an object of the image, formed at infinity. Microscopes are used
to look at magnified images of small objects. A simple microscope (a “magnifying glass”)
consists of a single convex lens. The lens is held close to the object so that the object is between
the lens and its focal point. When viewed from the other side of the lens, a magnified, virtual,
upright image is seen. The compound microscope is the most common type of microscope used
in laboratories. With these microscopes, an objective lens is used to create an inverted, real
image of the object. Using the eyepiece, the image is magnified. In this sense, its operating
principles are similar to that of a refracting telescope. The rear view mirror is a convex mirror
which forms a virtual and erect image of the object which is smaller in length than the object.
Because the image formed is smaller in length, it appears to be farther away and hence, the
warning written on it. This is because of the phenomenon of refraction of light as it crosses the
medium of water(refractive index greater than that of air). As the light ray travels from
water(denser medium) to air(rarer medium), the light ray bends away from the normal and the
image of the bottom of the stream seems to be raised and hence, the stream appears to be
shallower. a) In optics, chromatic aberration (CA, also called chromatic distortion, and
spherochromatism) is an effect resulting from dispersion in which there is a failure of a lens to
focus all colors to the same convergence point. It occurs because lenses have different refractive
indices for differentwavelengths of light. b) Optical Aberrations are departures of the
performance of an optical system from the predictions of paraxial optics. Aberration leads to

2. blurring of the image produced by an image-forming optical system. It occurs when light from
one point of an object after transmission through the system does not converge.