Question

A cheap replica is made of an old camera. If the lens in the old camera was glass, and the lens in the replica is plastic with a smaller index of refraction than the glass, in order to have the same focal length the plastic lens will have to ___.

a. have the same curvature as the glass lens

b. be less strongly curved than the glass lens

c.be more strongly curved than the glass lens

Answer #1

For a lens in a photo camera to make a real and
diminishedimage of an object, the object has to be
placed:
A. between the focal point of the lens and the lens
B. between the focal point and the center of curvature
C. at a distance greater than twice of the focal length of the
lens but less than “infinity”
D. at any distance in front of the camera

The crystalline lens of the human eye is a double-convex lens
made of material having an index of refraction of 1.46. We shall
assume that the radii of curvature of its two surfaces have the
same magnitude. Assume the lens is embedded in a fluid having
refractive index similar to air.
If the radii of curvature of this lens is 7.82mm, what is its
focal length?
If an object 10.0 mm tall is placed 17.0 mm from the eye lens,...

1. A spherical lens converges rays
a) more than a semi-sphere b) same as the hemisphere c0 less
than the hemisphere d) none
2. For the hemisphere (curved side facing the incident light),
the convergence of the rays, as the index of refraction increases
from air to glass.
a) increases b) decreases c) none d) no change
3. For the concave object (curved side facing the incident
light), the divergence of the rays, as the index of refraction
increases from...

One side of a lens is concave with the radius of curvature of
25cm, and the other side is flat. The lens is made of glass with
index of refraction of 1.5. Find the focal power of the lens? What
is the type of lens (coverging or diverging)?

A converging lens is made using glass with index 1.5. The
desired focal length is 60 cm. If one side of the lens is convex
with radius of curvature 20 cm, how should the other side be
made?

A single by bi-convex lens made of glass (index of refraction
n=1.50 ) has surfaces with the radii of curvature R1= 26.0 cm and
R2= -26 cm. (a) What is this focal length of the lens in the air?
(b) if an object is placed at p=32 cm from the lens, where is the
image? (Use plus sign for a real image, minus signs for the
virtual.) (c) if the subject has a height of h+1.50 cm, how large
is...

A single bi-concave lens (a lens with two concave surfaces) made
of glass (index of refraction n = 1.55) has surfaces with radii of
curvature r1 = -19.0 cm and r2 = 19.0 cm.
What is the focal length of the lens in air?
I got 17.32cm as the correct answer. Dont know the other
two.
If an object is placed at p = 20.0 cm from the lens, where is
the image? (Use a positive sign for a real...

You are given a lens made of glass with an index of refraction,
n = 1.45, and radii of curvature, R1 = 10 cm and
R2 = -80 cm.
a) Calculate the focal length of this lens.
b) A 5 cm tall object is placed 30 cm in front of this lens.
Determine the image distance and the height of the image. Is the
image upright or inverted?
c) Draw a diagram to illustrate with the object and image
positions...

A lens was made out of Diamond in order to take advantage of the
material’s refractive index. However, diamond also has a high
dispersion. What is the chromatic aberration limited resolution of
a telescope made from diamond lenses if the objective lens has a
focal length fO=25m and the eyepiece lens has a focal length
fE=2.5cm? Ignore the chromatic aberrations due to the eyepiece.
(Diamond index of refraction for red light nr=2.451, for violet
light nv=2.407).

Which of the following is true about lenses? Assume all
lenses have the same diameter and are made of glass.
a) The best digital cameras have the smallest
lenses.
b) The focal length of a lens is twice the distance from
the center of a lens to the focal point.
c) A lens made with material with a lower refractive
index has a shorter focal length.
d) A large diameter lens in a camera can only take
pictures in bright...

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