Problem 60
An object is placed \(20.0 \mathrm{cm}\) from a converging lens with focal length \(15.0 \mathrm{cm}\) (see the figure, not drawn to scale). A concave mirror with focal length \(10.0 \mathrm{cm}\) is located \(75.0 \mathrm{cm}\) to the right of the lens. (a) Describe the final image- -is it real or virtual? Upright or inverted? (b) What is the location of the final image? (c) What is the total transverse magnification?
Problem 61
Two lenses, of focal lengths \(3.0 \mathrm{cm}\) and \(30.0 \mathrm{cm},\) are
used to build a small telescope. (a) Which lens should be the objective? (b)
What is the angular magnification? (c) How far apart are the two lenses in the
telescope?
Problem 62
(a) If Harry has a near point of \(1.5 \mathrm{m},\) what focal length contact
lenses does he require? (b) What is the power of these lenses in diopters?
Problem 63
An astronomical telescope provides an angular magnification of 12. The two
converging lenses are \(66 \mathrm{cm}\) apart. Find the focal length of each of
the lenses.
Problem 64
Two lenses, separated by a distance of \(21.0 \mathrm{cm},\) are used in
combination. The first lens has a focal length of \(+30.0 \mathrm{cm} ;\) the
second has a focal length of \(-15.0 \mathrm{cm} .\) An object, $2.0
\mathrm{mm}\( long, is placed \)1.8 \mathrm{cm}$ before the first lens. (a) What
are the intermediate and final image distances relative to the corresponding
lenses? (b) What is the total magnification? (c) What is the height of the
final image?
Problem 65
A camera lens has a fixed focal length of magnitude \(50.0 \mathrm{mm} .\) The
camera is focused on a 1.0 -m-tall child who is standing \(3.0 \mathrm{m}\) from
the lens. (a) Should the image formed be real or virtual? Why? (b) Is the lens
converging or diverging? Why? (c) What is the distance from the lens to the
film? (d) How tall is the image on the film? (e) To focus the camera, the lens
is moved away from or closer to the film. What is the total distance the lens
must be able to move if the camera can take clear pictures of objects at
distances anywhere from \(1.00 \mathrm{m}\) to infinity?
Problem 66
A camera with a 50.0 -mm lens can focus on objects located from $1.5
\mathrm{m}$ to an infinite distance away by adjusting the distance between the
lens and the film. When the focus is changed from that for a distant mountain
range to that for a flower bed at \(1.5 \mathrm{m},\) how far does the lens move
with respect to the film?
Problem 67
The area occupied by one frame on 35 -mm film is \(24 \mathrm{mm}\) by $36
\mathrm{mm}-\( see the figure with Problem \)16 .$ The focal length of the
camera lens is \(50.0 \mathrm{mm}\). A picture is taken of a person $182
\mathrm{cm}$ tall. What is the minimum distance from the camera for the person
to stand so that the image fits on the film? Give two answers; one for each
orientation of the camera.
Problem 68
A dissecting microscope is designed to have a large distance between the
object and the objective lens. Suppose the focal length of the objective of a
dissecting microscope is \(5.0 \mathrm{cm},\) the focal length of the eyepiece
is \(4.0 \mathrm{cm},\) and the distance between the lenses is $32.0 \mathrm{cm}
.$ (a) What is the distance between the object and the objective lens? (b)
What is the angular magnification?
Problem 69
A cub scout makes a simple microscope by placing two converging lenses of +18
D at opposite ends of a \(28-\mathrm{cm}^{-}\) long tube. (a) What is the tube
length of the microscope? (b) What is the angular magnification? (c) How far
should an object be placed from the objective lens?
