PHYSICS 40 FINAL

(CH 25) A particle has a relativistic momentum of p. If its speed doubles, its relativistic momentum will be

A) less than 2p

B) equal to p

C) equal to (2p/hc)

D) greater than 2p

E) equal to 2p

D) greater than 2p

(CH 25) The equivalence principle says:

A) nothing can move faster than the speed of light

B) there is nothing special about our place in the Universe

C) a particle's position and momentum cannot both be known with high precision at the same time

D) an observer in a closed space cannot tell the difference between gravity and acceleration

D) an observer in a closed space cannot tell the difference between gravity and acceleration

(CH 27) In an atomic nucleus, the nuclear force binds

A) protons together

B) neutrons, protons, and electrons together

C) neutrons and protons together

D) neutrons together

E) electrons together

C) neutrons and protons together

(CH 27) The number of Polonium-210 atoms in a radioactive sample of 210Po

A) decreases linearly with time

B) decreases exponentially with time

C) remains constant

D) increases linearly with time

E) increases exponentially with time

B) decreases exponentially with time

(CH27) The half‑life for U-235U to decay to Pb-207 is 704 million years.

1. If 12.5% of the original U-235 remains in a rock sample, how many half‑lives of U-235 have occurred since the rock was formed?

A) 12.5 half lives

B) 3 half lives

C) 1/8 half lives

D) 8 half lives

2. How old is the rock?

A) 8.8 billion years

B) 2.11 billion years

C) 5.63 billion years

D) 88 million years

3. If only 3.125% of the original U-235 were remaining, how old would the rock be?

A) 22 million years

B) 22.5 billion years

C) 2.2 billion years

D) 3.52 billion years

1. B) 3 half lives

2. B) 2.11 billion years

3. D) 3.52 billion years

(CH27) Determine which of the nuclei has the largest mass defect per nucleon.

A) Ag-107

B) Pb-214

C) Cu-63

D) C-13

C) Cu-63

(CH23) When light enters a piece of glass from air with an angle of 𝜃 with respect to the normal to the boundary surface,

A) it bends with an angle larger than 𝜃 with respect to the normal to the boundary surface.

B) it does not bend.

C) it bends with an angle larger than 𝜃 with respect to the normal to the boundary surface.

D) it bends with an angle equal to 𝜃/2 with respect to the normal to the boundary surface.

E) it bends with an angle smaller than 𝜃 with respect to the normal to the boundary surface.

E) it bends with an angle smaller than 𝜃 with respect to the normal to the boundary surface.

(CH23) At which light level is diffraction less of a limiting factor in the sharpness of a person's vision?

A) diffraction is equally a factor in both intensities of light

B) dim

C) bright

D) more information is needed to answer

B) dim

(CH23) Which color of light, red or blue, travels faster in crown glass?

A) blue, but only if the glass is thin

B) it depends on the index of refraction

C) blue

D) red

E) their speeds are the same

D) red

(PL23) A laser beam is reflected by three parallel surfaces. How does incident angle compare with angle after final reflection?

A) incident > final reflected

B) incident < final reflected

C) incident = final reflected

C) incident = final reflected

(PL23) A ray of light bends as it passes from medium 1 to medium 2 such that the arrow inside the new medium has a shallower slope. Compare the indices of refraction.

A) n1 = n2

B) n1 < n2

C) n1 > n2

C) n1 > n2

(PL23) A light ray travels in a medium with an index of refraction n1 and completely reflects from the surface of a medium with index of refraction n2. The critical angle depends on

A) n1 only

B) both n1 and n2

C) n2 only

B) both n1 and n2

(PL26) A thin layer of gasoline on water appears brightly colored in sunlight. From where do the colors come?

A) the interference of the various wavelengths of sunlight reflected at the air‑gasoline boundary

B) the interference of light waves reflected from the opposite surfaces of the gasoline film

C) the interference of light waves refracted by the opposite surfaces of the gasoline film

D) the interference of light waves of similar frequencies created by the dispersion of the sunlight by the gasoline film

B) the interference of light waves reflected from the opposite surfaces of the gasoline film

(PL26)

1. When white light shines on a thin film of soap, light is reflected from

A) the front surface of the film only.

B) the back surface of the film only.

C) both the front and back surfaces of the film.

2. This results in

A) interference between the reflected light rays.

B) refraction of the reflected light rays.

C) a Doppler shift in the frequency of the reflected light.

3. Colors are seen in the soap film because certain wavelengths of the reflected light

A) are canceled due to destructive interference.

B) are absorbed by pigments in the soap.

C) are refracted at different angles.

1. C) both the front and back surfaces of the film.

2. A) interference between the reflected light rays.

3. A) are canceled due to destructive interference.

(PL27) In a Young's double-slit experiment the center of a bright fringe occurs wherever waves from the slits differ in the distance they travel by a multiple of:

A) none of these

B) a half a wavelength

C) three-fourths of a wavelength

D) a fourth of a wavelength

E) a wavelength

E) a wavelength

(PL27) A beam of monochromatic light illuminates a slit of width 𝑤 and forms a diffraction pattern on a screen located a distance 𝐷≫𝑤 from the slit. For which color of incident light is the width of the central band greater?

A) blue

B) yellow

C) both are equal

B) yellow

(PL27) The photographs in the figure show the diffraction patterns created by red laser light when it passes through narrow, single slits. The wavelength of the light is the same in all three photographs, but the widths of the slits are different.

*(a) is one red stretch

*(b) has 13 segments of varying size and distancing

*(c) has three segments

Order the photographs according to the width of the slit used to create the diffraction pattern, from widest to narrowest.

A) a-b-c

B) a-c-b

C) b-c-a

D) c-b-a

C) b-c-a

(PL27) An experiment is set up to test the angular resolution of an optical device when red light (wavelength 𝜆r) shines on an aperture of diameter 𝐷 .

Which aperture diameter gives the best resolution?

A) 𝐷=(1/2)𝜆r

B) 𝐷=𝜆r

C) 𝐷=2𝜆r

C) 𝐷=2𝜆r

(PL28) Which is true when an object is moved farther from a plane mirror?

A) The height of the image decreases, and the image moves farther from the mirror.

B) The height of the image increases, and the image moves farther from the mirror.

C) The height of the image decreases, and the image moves closer to the mirror.

D) The height of the image stays the same, and the image moves farther from the mirror.

E) The height of the image stays the same, and the image moves closer to the mirror.

D) The height of the image stays the same, and the image moves farther from the mirror.

(PL28) The diagram shows the paths of three light rays incident upon, and reflecting from, a concave mirror. Which ray is incorrectly drawn?

*A goes through left focal point and emerges parallel

*B goes parallel and emerges though left focal point

*C goes through twice the length of the focal point and emerges parallel

A) A

B) B

C) C

C) C

(PL29) Consider three cases in which an object is placed some distance in front of a spherical mirror.

Case A: mirror is convex, object distance is greater than focal length

Case B: mirror is concave, object distance is less than focal length

Case C: mirror is convex, object distance is less than focal length

In which of the cases is the formed image virtual, upright, and smaller?

A) Case A

B) Case B

C) Case C

D) Cases A & B

E) Cases A & C

F) Cases B & C

E) Cases A & C

(PL29) When an object is placed farther from a convex mirror than the focal length, the image is

A) smaller and inverted.

B) larger and real.

C) smaller and real.

D) smaller and virtual.

E) larger and virtual.

D) smaller and virtual.

(PL29) A real image can form in front of

A) a concave mirror.

B) a convex mirror.

C) no mirrors.

D) any type of mirror.

E) a plane mirror.

A) a concave mirror.

(PL31) Consider two cases involving the acceleration of an electron.

Case A: Accelerating an electron from rest to 0.9𝑐

Case B: Accelerating the same electron from 0.9𝑐 to 0.99𝑐

Which case requires more energy?

A) Case A

B) Case B

C) about the same

B) Case B

(PL32) Consider three cases where two protons are separated by a center‑to‑center distance of 1.5 fm.

Case A: Coulomb force out > strong force in

Case B: Coulomb force out = strong force in

Case C: Coulomb force out < strong force in

Which case best represents the relative magnitudes of the strong and Coulomb forces between the two protons?

A) Case A

B) Case B

C) Case C

C) Case C

(PL32)

1. Identify the fundamental forces that dominate nuclear structure.

A) Electromagnetic force

B) Strong force

C) Weak force

D) Gravitational force

For stable, have atomic nuclei, the number of neutrons is 2. (fewer than, greater than, equal to) the number of protons. This relationship occurs because additional 3. (protons, electrons, neutrons) increase the 4. (electromagnetic repulsion, gravitational attraction, strong force attraction) necessary to counteract the 5. (electromagnetic attraction, weak decays, electromagnetic repulsion) generated by the number of 6. (electrons, protons, neutrons).

1. A) Electromagnetic force & B) strong force

2. greater than

3. neutrons

4. strong force attraction

5. electromagnetic repulsion

6. protons

(PL33) The plot shows the data from three cases of an experiment performed to test for radioactive decay. 𝑁0 represents the original number of nuclei in the sample, and 𝜏 represents the half‑life.

Case A: exponential, slope decreases (curve faces up)

Case B: linear constant negative slope

Case C: exponential, slope increases (curve faces down)

A) Case A

B) Case B

C) Case C

Case A: exponential, slope decreases (curve faces up)

(PL33) A certain radioactive isotope has a half‑life of five days.

About how long will it take before 1/1000 of an initial sample of this isotope remains?

A) 20 days

B) 40 days

C) 50 days

D) 100 days

E) 1000 days

C) 50 days

(PL33) The decay series of U‑235 is shown. Identify the indicated decays as an alpha decay or a beta decay.

1. (231/90)Th -> (231/91)Pa

2. (227/89)Ac -> (223/87)Fr

3. (219/85)At -> (215/83)Bi

4. (227/90)Th -> (223/88)Ra

5. (215/84)Po -> (215/85)At

6. (207/81)Tl -> (207/82)Pb

1. beta decay

2. alpha decay

3. alpha decay

4. alpha decay

5. beta decay

6. beta decay

(PL30) A converging lens is used to project the image of an arrow onto a screen, as shown. object, lens, screen/image If a diverging lens replaces the converging lens, and nothing else changes,

A) the image formed is real and upright.

B) the image formed is virtual and inverted.

C) no image is projected onto the screen.

C) no image is projected onto the screen.

(HW7) 1. Which of the following describes Huygens' principle?

A) Tiny wavelets form expanding concentric circles or spheres around a wave source.

B) A wave crest is a source of tiny wavelets that define a wave front.

C) Wavelets travel at different speeds in different materials.

D) A wavelet travels in a straight line until it strikes a boundary between materials.

2. Why is Huygens' principle necessary to understand Snell's law of refraction?

According to Huygens' principle, a wavefront bends at a boundary between media because

A) each wavelet may travel a different distance in a given time in different media.

B) each wavelet reconstructs itself at the boundary between media.

C) the amplitude of each wavelet changes as the wave reaches a different media.

D) each wavelet changes its direction of travel at the boundary between media.

1. B) A wave crest is a source of tiny wavelets that define a wave front.

2. A) each wavelet may travel a different distance in a given time in different media.

(HW7) Which optical phenomenon is responsible for monochromatic light traveling along the path shown in the figure? light enters a triangular prism, bends down when crossing the first boundary, exits and bends down more after crossing the boundary on the other side

A) reflection

B) dispersion

C) total internal reflection

D) refraction

E) polarization

D) refraction

(HW7) When light enters a piece of glass from air with an angle of 𝜃 with respect to the normal to the boundary surface,

A) it bends with an angle equal to 𝜃2 with respect to the normal to the boundary surface.

B) it does not bend.

C) it bends with an angle smaller than 𝜃 with respect to the normal to the boundary surface.

D) it bends with an angle larger than 𝜃 with respect to the normal to the boundary surface.

E) it bends with an angle equal to 2𝜃 with respect to the normal to the boundary surface.

C) it bends with an angle smaller than 𝜃 with respect to the normal to the boundary surface.

(HW7) Which wave types refract when crossing from one medium to another?

A) water waves

B) only electromagnetic and sound waves

C) sound waves

D) electromagnetic waves

E) electromagnetic, sound, and water waves

E) electromagnetic, sound, and water waves

Classify statements about total internal reflection as true or false.

A) When light hits a boundary at an angle greater than the critical angle, it will undergo total internal reflection.

B) A larger critical angle means that total internal reflection is more likely to occur.

C) Magnifying glasses are a practical application of the phenomenon of total internal reflection.

D) Total internal reflection is more efficient than simple reflection of light off a silvered mirror, so prisms are often used in optical instruments to minimize light loss.

A) True

B) False

C) False

D) True

(HW7) Two linear polarizing filters are placed one behind the other, so that their transmission directions are parallel to one another. A beam of unpolarized light of intensity 𝐼0 is directed at the two filters.

What intensity of the light will pass through both filters?

A) 0.5𝐼0

B) 0.25𝐼0

C) 0

D) 𝐼0

E) 2𝐼0

A) 0.5𝐼0

(HW8) Two sets of parallel waves with the same wavelength but different initial phases are directed at a barrier. Each wave is incident on a single tiny hole in the barrier, as shown in the diagram, with the lines representing the peaks of the waves. The two holes, therefore, act as sources of spherical waves, which spread out and interfere with each other.

Determine what kind of interference occurs at each labeled point, and classify the points according to whether they correspond to regions of completely constructive interference, completely destructive interference, or in‑between.

A) on both red and blue

B) on red but close to blue

C) on red, not close to blue

D) on blue but close to red

E) on nether red nor blue

F) on blue, not close to red

A) constructive interference

B) in between

C) destructive interference

D) in between

E) constructive interference

F) destructive interference

(HW8) A tabletop two-slit interference experiment consists of a laser pointer shining through two narrow, closely spaced slits in an opaque barrier. Place each modification according to the effect it would have on the spacing between the bright spots on the wall (spacing increases, spacing decreases, no effect). In each case, assume that everything else is held constant.

A) increasing the wavelength of the laser light

B) increasing the distance d between the two slits in the barrier

C) increasing the brightness of the laser light

D) increasing the distance x from the laser to the slits

E) increasing the distance L from the slits to the wall

A) spacing increases

B) spacing decreases

C) no effect

D) no effect

E) spacing increases

(HW8) A monochromatic light passes through a narrow slit and forms a diffraction pattern on a screen behind the slit. As the wavelength of the light decreases, the diffraction pattern

A) shrinks with all the fringes getting narrower.

B) becomes dimmer.

C) spreads out with all the fringes getting alternately wider and then narrower.

D) spreads out with all the fringes getting wider.

E) remains unchanged.

A) shrinks with all the fringes getting narrower.

(HW8) Place the wavelengths at which a telescope performs observations in order of resolution, from worst resolution to best resolution.

A) gamma rays

B) infrared

C) microwaves

D) ultraviolet

E) visible

C-B-E-D-A

(HW9) Select the options that explain the meaning, in terms of physics, of the phrase etched on the right‑side mirror of most cars: "Objects in mirror are closer than they appear."

The image created by the right-side mirror is 1. (unchanged, smaller, larger) relative to the object's size, and as a result the object appears farther away. The image is also 2. (upright, inverted) and therefore 3. (real, virtual). Given the facts, the right-side mirror is 4. (concave, convex, plane).

1. smaller

2. upright

3. virtual

4. convex

(HW9) In order to manufacture a contact lens that causes incoming light rays to diverge, the radius of curvature of the front surface must be _______ that of the back surface.

A) less than

B) equal to

C) greater than

2. If this contact lens were placed in a medium with a refractive index 𝑛 that is greater than the refractive index 𝑛 of the lens, how would it behave?

A) It would continue to behave like a diverging lens.

B) It would behave like a converging lens.

C) It would transmit parallel light rays undeflected.

1. C) greater than

2. B) It would behave like a converging lens.

(HW9) You have a lens which has a negative focal length and create an image with a negative image distance.

1. Is the image real or virtual?

A) real

B) virtual

C) cannot be determined

2. Is the image upright or inverted with respect to the object?

A) cannot be determined

B) upright

C) inverted

1. B) virtual

2. B) upright

(HW9) A human eye has a positive near point and a positive far point. Is the focusing mechanism of the eye a diverging or converging lens?

A) converging lens

B) diverging lens

A) converging lens

(HW9) Is it possible to accelerate a massive object to the speed of light in a real situation? Explain your answer.

A) Yes, it is possible. Velocity is the product of acceleration and time, and therefore all objects can reach the speed of light if accelerated long enough.

B) No, it is not possible. Accelerating a massive object to the speed of light would require infinite energy.

C) No, it is not possible. As an object's length contracts towards zero, the work that can be done on it also approaches zero.

D) Yes, it is possible. Objects may be accelerated up to but not beyond the speed of light because it is the ultimate speed limit.

B) No, it is not possible. Accelerating a massive object to the speed of light would require infinite energy.

(HW10) A simple idea of nuclear physics can be stated as follows: "The whole nucleus weighs less than the sum of its parts." Why does a whole nucleus weigh less than the sum of its parts?

A) An energy input is required to overcome the strong nuclear force and break a nucleus into its individual nucleons. Because of mass‑energy equivalence, the added energy becomes mass after the nucleus breaks apart.

B) The strong nuclear force uses energy from the nucleus to bind individual nucleons together. Thus, the nucleus has less energy than the sum of its parts, and by energy‑mass equivalence, the nucleus weighs less.

C) The Coulomb force is a repulsive force between protons in the nucleus, thus the nucleus releases energy into the individual nucleons when it decays. According to Einstein, the added energy adds mass to the nucleons.

D) The individual nucleons move faster than the nucleus they form, so their kinetic energy is greater than that of the nucleus, making the sum of their masses greater than the nucleus mass, according to 𝐸=𝑚𝑐2.

A) An energy input is required to overcome the strong nuclear force and break a nucleus into its individual nucleons. Because of mass‑energy equivalence, the added energy becomes mass after the nucleus breaks apart.

(HW10) The mass of a nucleus is ______________________________ the sum of the masses of its nucleons.

A) sometimes less than

B) sometimes equal to

C) always less than

D) always equal to

E) always more than

C) always less than

(HW10) Which of the statements is true for fission processes?

A) Only the total number of neutrons remains the same.

B) Only the total number of protons remains the same.

C) Only the total number of nuclei remains the same.

D) The total number of protons and the total number of nuclei both remain the same.

E) The total number of protons and the total number of neutrons both remain the same.

E) The total number of protons and the total number of neutrons both remain the same.

(HW10) What is the source of the Sun's energy?

A) chemical reactions

B) gravitational collapse

C) both fusion reactions and fission reactions

D) fusion reactions

E) fission reactions

D) fusion reactions

(HW10) A series of decays is shown in graphical form. x loses 2 protons and 2 neutrons, y gains a proton but loses a neutron

Identify the kind of decay that corresponds to each arrow.

A) The arrow labeled 𝑥 corresponds to an alpha decay and the arrow labeled 𝑦 corresponds to a positron emission.

B) The arrow labeled 𝑥 corresponds to a beta decay and the arrow labeled 𝑦 corresponds to an alpha decay.

C) The arrow labeled 𝑥 corresponds to an alpha decay and the arrow labeled 𝑦 corresponds to a beta decay.

D) The arrow labeled 𝑥 corresponds to a positron emission and the arrow labeled 𝑦 corresponds to an alpha decay.

C) The arrow labeled 𝑥 corresponds to an alpha decay and the arrow labeled 𝑦 corresponds to a beta decay.

(HW10) Ruthenium-106 decays by 𝛽− emission with a half‑life of 373.59 days.

1. How many protons and neutrons does the ruthenium-106 nucleus contain?

2. Could we expect to find significant amounts of ruthenium-106 in ore mined from the ground? Why or why not?

A) No, because the last remaining ruthenium-106 nucleus will decay after two half‑lives. Since ore takes many years to form, the two half‑lives will already have passed.

B) Yes, because the rate of decay decreases with time. Thus, most of the ruthenium-106 will stop decaying after only a few half‑lives have passed.

C) Yes, because ruthenium-106 has a large mass number. A large mass number implies it is more stable, and therefore, it decays more slowly and will remain long enough for the ore to form.

D) No, because its half‑life is too small relative to the time interval required for ore to form. A relatively small half‑life implies a greater probability that only a small portion of ruthenium-106 will remain long enough for the ore to form.

3. Write the decay equation for ruthenium-106.

1. 44, 62

2. D) No, because its half‑life is too small relative to the time interval required for ore to form. A relatively small half‑life implies a greater probability that only a small portion of ruthenium -106 will remain long enough for the ore to form.

3. 106Rh, e-, Ve-

(HW10) The decay rate for any isotope

A) remains constant.

B) increases linearly with time.

C) decreases linearly with time.

D) increases exponentially with time.

E) decreases exponentially with time.

E) decreases exponentially with time.

(HW10) The number of Polonium-210 atoms in a radioactive sample of Po210

A) decreases linearly with time.

B) increases linearly with time.

C) decreases exponentially with time.

D) remains constant.

E) increases exponentially with time

C) decreases exponentially with time.

(HW10) The decay constant 𝜆 depends only on

A) the number of atoms at the initial time.

B) the half‑life.

C) the temperature of the sample.

D) the initial decay rate.

E) the external gravitational field.

B) the half‑life.

(CH23) If light crossing a boundary between two media has a slower speed in the second medium, the refracted ray will 1. (bend toward normal, not bend at all, bend away from normal). If light crossing a boundary between two media has a faster speed in the second medium, the refracted ray will 2. (bend toward normal, not bend at all, bend away from normal).

1. bend toward normal

2. bend away from normal

(CH23) Because of dispersion, in most materials, the index of refraction for visible light 1. (increases, decreases, remains the same) from red to blue because red has a 2. (higher, lower) frequency and a 3. (longer, shorter) wavelength than blue.

1. increases

2. lower

3. longer

(CH23) DEFINITIONS

reflection:

refraction:

total internal reflection:

dispersion:

polarization:

thin film interference:

soap film interference:

diffraction:

angular resolution:

reflection: angle of reflected light is equal to angle of incidence (light bounces back out)

refraction: change in direction (and therefore angle) of light that crosses boundary between two media

total internal reflection: occurs when incident angle is equal to the critical angle and all of the light reflects back into medium 1 without entering medium 2

dispersion: variation with frequency in the speed of light in different media (due to their different indices of refraction, different colors reflect at different angles)

polarization: orientation of oscillating electric field in a light wave (when incident angle is equal to Brewster's angle, light reflected from the boundary between two media is completely polarized parallel to the boundary)

thin film interference: when a single beam of light strikes a film of transparent material, some light is reflected from the front surface while some enters film and is reflected from the back surface (whether resulting interference is constructive or destructive depends on the number of wave cycles that fit in the path difference)

soap film interference: same principle as for thin films, but equations for constructive vs destructive flip

diffraction: the tendency of waves to spread out when they pass through a narrow opening or near a sharp edge of an object

Rayleigh's angular resolution: angle separating two point objects can be resolved through circular aperture if center of bright max for one coincides with dark fringe of the other (smaller angle = better resolution = smaller details can be resolved BUT limited by diffraction which blurs images)

(CH24) DEFINITIONS

mirrors

lens

virtual image

real image

focal point

focal length

center of curvature

radius of curvature

camera lens

human eye

corrective lens

mirrors: form images by the reflection of light from the mirror's surface

lens: form images by the refraction of light as it enters and exits the lens

virtual image: no light rays actually pass through at the location of the image (ex: plane mirror)

real image: formed by light rays coming together

focal point: point along the principle axis at which incident rays parallel to it converge to a common focus when they reflect off the mirror

focal length: distance from focal point to center of curvature

center of curvature: center of the sphere of which the mirror is a part

radius of curvature: distance from the center of curvature to any point on the mirror

camera lens: refracts parallel light rays onto light-sensitive sensor (to focus, lens moves away from sensor or focal length diminishes)

human eye: refraction occurs in cornea and lens to focus rays on the retina (adjusting focus occurs by reshaping the lens)

corrective lens: change the amount by which light rays are forced to converge within the eye on their way to the retina

(CH27) DEFINITIONS

alpha radiation

beta minus radiation

beta plus radiation

gamma radiation

alpha radiation: loss of 2 protons and 2 neutrons to form an alpha particle, energy released, daughter more tightly bound

beta minus radiation: loss of neutron to generate proton, electron, and anti-neutrino (A is unchanged)

beta plus radiation: loss of proton to generate neutron, positron, and neutrino (A is unchanged)

gamma radiation: no change in protons or neutrons, emits high energy photon in going from an excited state to ground state

(CH24) Which is true when an object is moved farther from a plane mirror?

A) The height of the image decreases, and the image moves closer to the mirror.

B) The height of the image stays the same, and the image moves farther from the mirror.

C) The height of the image stays the same, and the image moves closer to the mirror.

D) The height of the image increases, and the image moves farther from the mirror.

E) The height of the image decreases, and the image moves farther from the mirror.

B) The height of the image stays the same, and the image moves farther from the mirror.

(CH24) When a dentist needs a mirror to see an enlarged, upright image of a patient's tooth, what kind of mirror should she use?

A) a plane mirror

B) a convex mirror

C) a concave mirror

D) either a plane mirror or a convex mirror

E) either a plane mirror or a concave mirror

C) a concave mirror

(CH25) If you want to start a fire using sunlight, which kind of mirror would be most efficient?

A) a convex mirror

B) It is not possible to start a fire using sunlight and a mirror; you must use a convex lens.

C) a plane mirror

D) any type of plane, concave, or convex mirror

E) a concave mirror

E) a concave mirror

(CH24) An object is placed at the center of curvature of a concave mirror. The image is

A) real and inverted.

B) virtual and upright.

C) virtual and inverted.

D) real and upright.

E) nonexistent; no image is formed.

A) real and inverted.

(CH24) When an object is placed a little farther from a concave mirror than the focal length, the image is

A) magnified and real.

B) smaller and reversed.

C) magnified and virtual.

D) smaller and virtual.

E) smaller and real.

A) magnified and real.

(CH24) A real image can form in front of

A) a concave mirror.

B) a convex mirror.

C) any type of mirror.

D) no mirrors.

E) a plane mirror.

A) a concave mirror.

(CH24) When an object is placed farther from a convex mirror than the focal length, the image is

A) larger and real.

B) smaller and virtual.

C) smaller and inverted.

D) smaller and real.

E) larger and virtual.

B) smaller and virtual.

(CH24) You hold a convex lens a few centimeters from your face and look through it at a tree. The tree is actually 14m away from you, but the image you see appears to be even farther away (19 m). Is the image you are looking at a real or virtual image?

A) real

B) neither

C) It depends on the focal length of the lens.

D) virtual

D) virtual

(CH24) A magnifier allows one to look at a very near object by forming an image of it farther away. The object appears larger. To create a magnifier, one would use a

A) short focal length convex lens.

B) long focal length concave lens.

C) short focal length concave lens.

D) long focal length convex lens.

E) either a convex or a concave lens.

A) short focal length convex lens.

(CH24) CONCAVE MIRRORS

-sign of focal point

-meaning of positive image distance

-types of rays in diagram

-types and locations of images produced

-f is positive

-positive d(i) means image on same side as object

rays

-1: parallel to principle axis, reflects through left focal point

-2: directed at principle axis, reflects with same angle as incident

-3: through left focal point, reflects parallel to principle axis

types/locations of images formed

-outside C: real inverted smaller

-at C: real inverted same size

-between C and f: real inverted larger

-at f: no image

-inside f: virtual upright larger

(CH24) CONVEX MIRRORS

-sign of focal point

-meaning of positive image distance

-types of rays in diagram

-types and locations of images produced

f is negative

positive d(i) means image on same side as object

rays

-1: parallel to principle axis, reflects out and traces back through right.far focal point

-2: directed at principle axis, reflects with same angle as incident

-3: directed through lens toward far/right focal point, reflects parallel to principle axis

types/locations of images formed: ALWAYS virtual, upright, larger, and closer to mirror

(CH24) CONVERGING/CONVEX LENSES

-sign of focal point

-meaning of positive image distance

-types of rays in diagram

-types and locations of images produced

f is positive

positive d(i) means image on opposite side from object

rays

-1: parallel to principle axis, refracts through right/far focal point

-2: goes through principle axis in straight continuous line

-3: crosses left/near focal point then exits parallel to principle axis

types/locations of images formed

-outside f: real inverted

-at f: no image formed (rays parallel)

-inside f: virtual upright larger

(CH24) DIVERGING/CONCAVE LENSES

-sign of focal point

-meaning of positive image distance

-types of rays in diagram

-types and locations of images produced

f is negative

positive d(i) means image on opposite side from object

rays

-1: parallel to principle axis, traces back through left/near focal point

-2: goes through principle axis in straight continuous line

types/locations of images formed: ALWAYS virtual upright smaller

(CH24) A 3.71 mm high diamond is placed on the axis of, and 10.3 cm from, a lens with a focal length of −6.15 cm.

1. If it can be determined, is the diamond's image real or virtual?

A) real

B) cannot be determined

C) virtual

2. If it can be determined, is the image upright or inverted with respect to the real thing?

A) inverted

B) cannot be determined

C) upright

1. C) virtual

1. C) upright

(CH24) A 8.97 mm high chocolate chip is placed on the axis of, and 10.9 cm from, a lens with a focal length of 5.49 cm.

1. If it can be determined, is the chocolate chip's image real or virtual?

A) cannot be determined

B) real

C) virtual

2. If it can be determined, is the image upright or inverted with respect to the real thing?

A) inverted

B) upright

C) cannot be determined

1. B) real

2. A) inverted

(CH24) Consider a converging lens whose focal length is 6.49 cm. An object is placed on the axis of the lens at a distance of 12.3 cm from the lens.

1. If it can be determined, is the image real or virtual?

A) real

B) cannot be determined

C) virtual

2. If it can be determined, is the image upright or inverted with respect to the object?

A) inverted

B) upright

C) cannot be determined

1. A) real

2. A) inverted