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85 Cards in this Set
- Front
- Back
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The potential energy of an electric dipole p in a region of electric field E is
U = -pE cosq. U = +pE sinq. U = +pE cosq. U = -pE/q0. U = -pE sinq. |
U = -pE cosq.
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The electric field at the outer surface of a positively charged conductor is always directed
- normal to the surface and outward. - at an angle intermediate between the normal and the tangential directions. - tangential to the surface. - There is no direction because the field at the surface of a conductor is always zero. - normal to the surface and inward. |
normal to the surface and outward.
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The electric field at a point in space is defined as
- a vector in the direction of the force that acts on a small positive test charge placed at that point. The magnitude of the field is given by the product of that force with the test charge. - a vector in the direction of the force that acts on a small positive test charge placed at that point. - a scalar proportional to the force that acts on a small positive test charge placed at that point. - a vector in the direction of the force that acts on a small negative test charge placed at that point. - a scalar proportional to the force that acts on an electron (negative charge) placed at that point. |
a vector in the direction of the force that acts on a small positive test charge placed at that point.
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The lines of electric field produced by an electric dipole are directed
- radially inward toward the center of the dipole. - from the negative charge to the positive charge. - radially outward from the center of the dipole. - from the positive charge to the negative charge. - in circular loops about the symmetry axis of the dipole and thus in the plane perpendicular to the dipole moment. |
from the positive charge to the negative charge.
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An electric dipole placed in a region of uniform electric field experiences
- a net linear acceleration transverse to the applied electric field. - a net torque causing the dipole moment to align with the electric field. - a net force that drives the dipole in the direction of the external field. - a net torque causing the dipole moment to align at right angles to the electric field. - a net torque causing the dipole moment to align opposite to the direction of the electric field. |
a net torque causing the dipole moment to align with the electric field.
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The capacitance of a parallel plate capacitor is
proportional to the area of the plates. proportional to the separation between the plates. proportional to both the area between the plates and the separation between the plates. proportional to the charge on the plates. proportional to the electric field between the plates. |
proportional to the area of the plates.
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Suppose a parallel plate capacitor is charged and the source of charge is then disconnected. If the plates of the capacitor are pulled farther apart
- the electric charge on the plates will decrease. - the electric potential difference between the plates will remain unchanged. - the electric potential difference between the plates will decrease. - the electric charge on the plates will increase. - the electric potential difference between the plates will increase |
the electric potential difference between the plates will increase
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The electric potential at a distance r from a point charge q is
- proportional to r. - inversely proportional to r. - proportional to 1/r2. - proportional to r2. |
inversely proportional to r.
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The gradient of the electric potential is called the
- electric charge. - capacitance. - electric field. - equipotential. - Coulomb. |
electric field.
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A circuit in which the path for current has been broken is commonly called
- an open circuit. - a closed circuit. - a grounded circuit. - an occluded circuit. - a short circuit. |
an open circuit.
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The terminal potential difference (voltage) measured for a cell (battery) is typically less than the emf because
- some of the current leaks away. - the battery has no source of charge. - the battery is not fully charged. - the battery has internal resistance. - the battery is a current sink. |
the battery has internal resistance.
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A circuit in which the current may bypass some of the desired elements is known as
- a short circuit. - a closed circuit. - an open circuit. - an obscure circuit. - an ungrounded circuit. |
a short circuit
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The SI unit for electric current is the
- farad. - coulomb. - volt. - henry. - ampere. |
ampere
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You have seen that electric field lines originate and terminate on electric charges. Magnetic field lines
- similarly originate and terminate on magnetic poles, but do not discriminate between north and south poles. - do not terminate but form continuous loops. - originate on north magnetic poles and terminate on south magnetic poles. - originate on south magnetic poles and terminate on north magnetic poles. - exist only in permanent magnets. |
do not terminate but form continuous loops.
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A common bar magnet with a single north pole and a single south pole is called a
- quadrupole. -octopus. - monopole. - dual pole. - dipole. |
dipole.
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When a charged particle enters a region of magnetic field moving along a direction parallel to the field, the path of the particle will be
- a circle. - a straight line. - an ellipse. - a parabola. - a helix. |
a straight line
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The magnitude of the torque t on a magnetic diole moment μ aligned at an angle θ in a magnetic field B is
- τ = μB tan θ - τ = (μ/B) sin θ - τ = (μ/B) cos θ - τ = μB cos θ - τ = μB sin θ |
τ = μB sin θ
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The emf induced in a coil of wire by a magnetic field is proportional to
- the magnetic flux density within the coil. - the rate of change of the magnetic flux enclosed by the coil. - the net magnetic flux within the coil. - electrical resistance of the coil. - the rate of rotation of the coil. |
the rate of change of the magnetic flux enclosed by the coil.
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An electromagnetic wave consists of
- longitudinal oscillations. - high speed electrons. - moving coupled electric and magnetic fields. - a mechanical disturbance of the ether. - high speed protons. |
moving coupled electric and magnetic fields
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Two identical bar magnets are dropped at the same time from the same height down tubes of the same length. Magnet A is dropped down an aluminum tube while magnet B is dropped down a plastic (non-conducting) tube. Which magnet reaches the bottom of the tubes first?
- Magnet A. - Magnet A will not fall through a conducting tube. - Magnet B. - The answer depends on the permeability of the plastic in the plastic tube. - Both arrive at the same time. |
Magnet B.
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The operation of an electrical transformer depends on
- Henry's law. - Coulomb's law. - Ampere's law. - Gauss's law. - Faraday's law. |
Faraday's law.
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For a given battery voltage, the final current in a series LR circuit is determined by
- the combination of resistance and inductance. - the inductive time constant only. - the inductance only. - the capacitance only. - the resistance only. |
the resistance only
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Imagine a series circuit of a capacitor, a resistor, a battery, and a switch. After the switch is closed, the current will
- reach a final value of one half its initial value. - reach a constant value in one time constant. - gradually approach zero. - slowly increase to its final steady-state value. - fall to zero in one time constant. |
gradually approach zero.
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After a time t = one time constant, the current in a RC circuit will be equal to
- 37% of its initial value. - 50% of its initial value. - zero. - 25% of its initial value. - 63% if its final value. |
37% of its initial value
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When a sinusoidal voltage is applied to a circuit containing reactance, the general result is that the current and voltage
- will not have an effective value. - will be exactly in phase. - will be out of phase. - will be equal. - will be zero. |
will be out of phase.
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Suppose you stand 3 feet from a plane mirror and face it. Where is your image?
- Your image lies in the plane of the mirror. - Your image lies half-way between you and the mirror. - Your image lies 6 feet behind the plane of the mirror. - Your image lies 3 feet in front of the plane of the mirror. - Your image lies 3 feet behind the plane of the mirror. |
Your image lies 3 feet behind the plane of the mirror.
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Your image in a plane mirror is
- erect and virtual. - inverted and virtual. - smaller than you are. - inverted and real. - erect and real. |
erect and virtual.
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Which of the following is true for a concave mirror?
- The image of a real object is always inverted. - The image of a real object may be virtual or real depending on the object distance. - The image of a real object is always smaller than the object. - The image of a real object is always larger than the object. - The image of a real object is always virtual. |
The image of a real object may be virtual or real depending on the object distance.
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Which of the following is true for a convex mirror?
- The image of a real object may be real or virtual depending on the object distance. - The image of a real object is always virtual. - The image of a real object is always inverted. - The image of a real object is always larger than the object. - The image is farther from the mirror than the object is to the mirror. |
The image of a real object is always virtual.
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A wide-angle mirror in a grocery store is made from a section of a sphere whose radius of curvature is 1.5 m. The image of a person standing 1.5 m in front of the mirror is
- inverted, virtual, and smaller than the person. - erect, real, and smaller than the person. - erect, virtual, and smaller than the person. - erect, virtual, and larger than the person. - inverted, real, and larger than the person. |
erect, virtual, and smaller than the person.
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What is the speed of light in glass that has an index of refraction of 1.5?
- 2 x 108 m/s - 0.5 x 108 m/s - 5 x 108 m/s - 4.5 x 108 m/s - 0.66 x 108 m/s |
2 x 108 m/s
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The plane of incidence is the
- plane that is normal to the incident and reflected rays. - mirror plane. - plane perpendicular to the incident and reflected rays. - reflecting plane. - plane that contains the incident ray and the reflected ray. |
plane that contains the incident ray and the reflected ray.
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Which of the following is true for a convex mirror?
- the image of a real object is always inverted - the image of a real object is always virtual - the image of a real object may be virtual or real depending on the object distance - the image is farther from the mirror than the object is to the mirror - the image of a real object is always larger than the object |
the image of a real object is always virtual
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A binocular is rated as 7 x 35. It has a magnification of __ ?
- 2.45 x - 5 x - Answer not given. - 35 x - 7 x |
7 x
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The Kodak Max single-use cameras have a lens with a focal length of about 33 mm. A lens of that focal length for a 35-mm camera is considered a _____
- normal lens. - telephoto lens. - wide-angle lens. - polarizing lens. - zoom lens. |
wide-angle lens.
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An astronomical telescope has a 30-cm-focal-length objective and an eyepiece with a focal length of + 5.0 cm. The magnification of the telescope is
- 24 x - 6 x - 12 x - 4 x - 30 x The image seen with the astronomical telescope of the previous problem is - rotated by 45o. - erect. - rotated by 90o. - Cannot be determined from the problem. - inverted. |
6 x
inverted |
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A student wears 2.5 diopter contact lenses. What is the focal length of these lenses?
- 25 cm - 4.0 m - 0.40 m - 4.0 cm - 2.5 m |
0.40 m
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A person with a near point of 15 cm is considered to be
- answer not given. - far sighted. - nearly blind. - hyperopic. -myopic. |
myopic
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Which lens admits more light, one with an f-number of 2.8 or one with an f-number of 5.6?
- Cannot say because it depends on the focal length. - Neither, they admit the same amount of light. - The lens with f-number 5.6. - Both, they admit the same amount of light. - The lens with f-number 2.8. |
The lens with f-number 2.8.
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A simple box camera has no adjustment for focusing, yet it can be used to record photos over a wide range of distances. This happens because the lens has
- a very large aperture. - a long focal length. - a small depth of field. - a long shutter time. - a large depth of field. |
a large depth of field.
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An interference pattern occurs when light from a helium-neon laser (l = 633 nm) is passed through a pair of closely-spaced narrow slits. If red light from a laser pointer with λ = 650 nm is used, the pattern changes so that the center-to-center distance between the interference maxima (bright spots) is
- twice as far apart. - half as far apart. - 2/3 as far apart. - unchanged. - slightly farther apart. |
slightly farther apart
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When light is passed through a narrow slit (slit width approaching the wavelength of the light) the light is
- Answer not given. - reflected. - refracted. - dispersed. - spread out by a process called diffraction. |
spread out by a process called diffraction
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We demonstrated the diffraction pattern made when light from a helium-neon laser (λ = 633 nm) was passed through a single narrow slit. If green light from a diode laser pointer with λ = 550 nm was used, the pattern would be changed so that the width of the central maxima (bright spot) would be
- unchanged. - greater. - 1/3 as great. - smaller. - half as great. |
smaller
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The colors in a soap bubble are due to
- total internal reflection. - diffraction. - interference. - dye pigments. - optical activity. |
interference
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Polarization of light is best understood using the
- wave model of light. - infrared color system. - using the particle model of light. - Snell's law. - using the ray model of light. |
wave model of light
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When light shines on a smooth dielectric surface at the Brewster angle, the reflected light is
- linearly polarized perpendicular to the reflecting plane. - circularly polarized perpendicular to the plane of incidence. - linearly polarized parallel to the plane of incidence. - linearly polarized perpendicular to the plane of incidence. - completely unpolarized. |
linearly polarized perpendicular to the plane of incidence
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In the lecture you saw that when a linear polarizer was placed in front of an LCD computer screen and rotated, at one position it completely blocked the view of the screen. From that observation we know that
- the light emerging from the screen is unpolarized. - something happened but we do not know why - the light emerging from the screen is linearly polarized. - the light emerging from the screen is circularly polarized. - the light emerging from the screen is partially polarized. |
the light emerging from the screen is linearly polarized.
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When light is passed through a very narrow slit, it spreads out into the geometric shadow region. We call this behavior
- reflection. - refraction. - optical activity. - diffraction. - interference. |
diffraction
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Antireflection coatings are put on lenses to
- correct for spherical aberrations. - correct for chromatic aberrations. - make the lenses stronger. - reduce effects of polarization. - allow the maximum amount of light to pass through. |
allow the maximum amount of light to pass through.
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When white light is passed through a triangular glass prism, the emerging light is dispersed into a spectrum of colors because
- the angle of reflection changes with the wavelength of the light. - of selective absorption within the glass. - of Brewster's law of polarization. - of total internal reflection. - the index of refraction of the glass changes with the wavelength of the light. |
the index of refraction of the glass changes with the wavelength of the light.
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An inertial frame of reference is
- a rotating frame of reference. -a frame in which Newton's laws of motion are valid. - a frame that is particularly heavy. - a frame in which the laws of physics are violated. - an accelerating frame of reference. |
a frame in which Newton's laws of motion are valid.
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In a muon experiment, the number of muons measured per hour at the top of a mountain was compared with the number measured at sea level. The number of muons expected at sea level was then computed from knowledge of the lifetime of the muons, their speed, and the additional distance traveled to reach sea level. The measured number of muons at sea level was greater than the simple computation predicted because
- time passed more slowly for the fast-moving muons. - moving muons have less total energy. - the distance was increased as seen from the moving frame of the muon. - time passes more quickly for the fast-moving muons. - the number of muons increased by radioactive decay on the way down. |
time passed more slowly for the fast-moving muons.
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The theory of relativity arose out of the need to reconcile Newtonian mechanics with
- Maxwell's electromagnetic theory. - atomic theory. - nuclear physics. - thermodynamics. - quantum theory. |
Maxwell's electromagnetic theory.
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A student in an inertial frame of reference moves with a speed v relative to a second inertial frame. The student shines a laser pointer in the direction of motion of his frame. An observer in the second frame measures the speed of the laser light to be:
- c + v. - c. - c - v. - v. - c/2. |
c
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Alpha particles are
- photons. - hydrogen nuclei. - electrons. - helium nuclei. - protons. |
helium nuclei
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The diameter of an atom is about
- 1.0 nm. - 1.0 pm. - 0.1 mm. - 0.1 nm. - 0.1 mm. |
0.1 nm.
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Electrons can be easily distinguished from photons because
- electrons are deflected by electric and/or magnetic fields, but photons are not deflected. - photons may be accelerated with magnetic fields. - electrons may possess momentum but photons cannot. - photons may carry energy but electrons do not. - photons are deflected by electric and/or magnetic fields, but electrons are not deflected. |
electrons are deflected by electric and/or magnetic fields, but photons are not deflected.
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The discovery of the atomic nucleus resulted from the experimental work of Geiger and Marsden in which
- gamma rays were scattered from lead blocks. - cathode rays were deflected by both electric and magnetic fields. - alpha particles were backscattered from a thin gold foil. - x rays were diffracted from crystals of zinc sulfide. - uranium salts were exposed to sunlight and caused the exposure of photographic plates. |
alpha particles were backscattered from a thin gold foil.
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X rays are
- helium nuclei. - high energy electromagnetic radiation. - high energy electrons. - high energy protons. - antiparticles to electrons |
high energy electromagnetic radiation.
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Cathode rays are beams of
- protons. - electrons. - alpha particles. - hydrogen ions. - photons. |
electrons
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The prober ordering of the elements in the periodic table was finally realized in the early 20th century by
- Henry J. G. Moseley. - Pierre Curie. - Marie Curie. - Max Planck. - Albert Einstein. |
Henry J. G. Moseley
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In an experiment, photoelectrons are emitted when light of intensity I and wavelength l is shined on a metal surface. The current due to these photoelectrons will increase if
- the intensity I of the light is increased. - if the frequency of the light is decreased. - the wavelength of the light is increased. - if the potential difference between the metal surface and the collecting electrode is decreased. - if the light is polarized. |
the intensity I of the light is increased
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The amount of energy required to release a photoelectron from a metal surface is usually called the
- series limit. - Rydberg constant. - work function. - ionization potential. - Planck constant. |
work function
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Which of the following persons first observed the dark lines in the solar spectrum?
- Johannes Rydberg - Joseph Fraunhoffer - Henry J. G. Moseley - J. J. Balmer - James Clerk Maxwell |
Joseph Fraunhoffer
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Planck's quantum theory of light arose from the study of
- radioactivity. - x rays. - the photoelectric effect. - light emitted from a hot object. - the Balmer lines. |
light emitted from a hot object.
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According to quantum mechanics, it is possible for a particle confined to a region surrounded by a high but narrow potential barrier to escape by
- relocating its energy. - the Compton effect. - converting its mass to energy. - tunneling. - climbing up and over the barrier. |
tunneling
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The intrinsic angular momentum of a particle is called its
- exclusion energy. - wavelength. - spin. - charge. - angular energy. |
spin
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In the experiment referred to as the Compton effect or Compton scattering, what did Compton observe?
- A change in the wavelength of the photons with a change in their velocity. - A change in the wavelength of the scattered electrons that depended on the angle through which they were scattered. - A correlation between the wavelengths seen in the spectrum of hydrogen. - A change in the wavelength due to the Doppler shift. - A change in wavelength of the scattered photons that depended on the angle through which they were scattered |
A change in wavelength of the scattered photons that depended on the angle through which they were scattered
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The analysis of the Compton effect assumes that x-ray photons
- follow the rules of classical physics. - cannot interact in a way that would change their momentum. - may be treated as particles having momentum and energy. - obey the Pauli exclusion principle. - cannot interact in a way that would change their wavelength. |
may be treated as particles having momentum and energy.
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The first experimental observation of deBroglie waves was made by
- W. L. Bragg who diffracted x rays from crystals. - Geiger and Marsden who scattered alpha particles off a gold foil. - G. P. Thompson who diffracted electrons from a thin foil. - C. J. Davisson and L. H. Germer who diffracted electron from silver. - Henry J. G. Moseley who scattered x ray off many different elements. |
C. J. Davisson and L. H. Germer who diffracted electron from silver.
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The SI unit of absorbed dose is the
- becquerel (Bq). - roentgen (R). - rad. -curie (Ci). - gray (Gy). |
gray GY
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The curie is a unit of radioactivity that is equal to
- 3.7 x 10^10 disintegrations/second. - 2.58 x 10^-4 disintegrations/second. - 4*pi*Gy. - 3.7 disintegrations/second. |
3.7 x 10^10 disintegrations/second.
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Cherenkov radiation, seen as a blue glow in water surrounding highly radioactive materials, is caused by
- electrons moving faster than the speed of sound in the water. - photons moving faster than the speed of light in the water. - neutrinos moving faster than the speed of light in the water. charged particles moving faster than the speed of light in the water. - charged particles moving faster than the speed of light in vacuuo. |
charged particles moving faster than the speed of light in the water.
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The term "isotopes" refers to nuclei with the
- same A, but different Z. - same number of nucleons and same number of protons. - same number of neutrons, but different number of protons. - same Z but different A. |
same Z but different A.
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The isotope fluorine-18 is the radioactive tracer used in PET scans. It is chosen because
- it is a positron emitter. - it is an xray emitter. - it is an alpha emitter. - it is a proton emitter. - it is a good source of pions. |
it is a positron emitter
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How does the size of a nucleus (its radius) depends on the number of nucleons A?
- The radius is proportional to A squared. - The radius is proportional to the cube root of A. - The radius is proportional to the square root of A. - The radius is inversely proportional to the cube root of A. - The radius is proportional to A cubed. |
The radius is proportional to the cube root of A.
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The antiparticle to the proton is the
- pion. - neutron. - positron. - antiproton. - electron. |
antiproton
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The neutrino, electron, muon, and tau are lumped together as a group of weakly interacting particles known collectively as
- hadrons. -baryons. - mesons. - leptons. - nucleons. |
leptons
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A positively charged pion (p+) decays into
- a proton and an a gamma ray. - a m+ and a m-. - an electron and a positron. - two gamma rays. - a m+ and a neutrino. |
a m+ and a neutrino.
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In the quark model of matter, mesons are made up of
- a quark-antiquark pair. - an electron and a quark. - three quarks. - two quarks and one antiquark. - two quarks. |
a quark-antiquark pair
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The particle that mediates the strong force is the
- electron. - muon. - positron. - photon. - pion. |
pion
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When a positron combines with an electron, they can disappear as a pair of photons are created. When that happens,
- the two photons emerge in opposite directions. One has an energy of 0.511 Mev and the other has an energy of 1.022 MeV. - the two photons emerge in opposite directions, each with an energy of 1.022 MeV. - the two photons emerge in opposite directions, each with an energy of 0.511 MeV. - the two photons emerge in the same direction, each with an energy of 0.511 MeV. - the two photons emerge at right angles, each with an energy of 0.511 MeV. |
the two photons emerge in opposite directions, each with an energy of 0.511 MeV.
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Consider a one-electron atom with a lowest state of energy E0 and a higher state E1. In a collection of such atoms we normally find that
- more atoms have electrons in state E0 than in E1. - All atoms have electrons in state E1. - equal numbers of atoms have electrons in state E0 as in E1. - more atoms have electrons in state E1 than in E0. |
more atoms have electrons in state E0 than in E1.
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Consider a one-electron atom with lowest energy state E0 and a higher state E1. The atom in its excited state E1 de-excites by radiation to state E0 by emitting a photon on energy Ep = E1 - E0. When the photon of energy Ep hits an atom with its electron in state E1 it is possible to get
- stimulated absorption of the photon. - creation of another atom. - spontaneous absorption of the photon. - spontaneous emission of a new photon of energy 2E1. - stimulated emission of another photon. |
stimulated emission of another photon.
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What do you see when looking at light reflecting off the wall that tells you that it is light from a laser? That is, that you are seeing coherent light?
- The speckle pattern. - Nothing, for there is no way to tell that it is laser light. - Its narrow collimated beam. - Its index of refraction. - Its red color. |
The Speckle pattern
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