phys b final review
Determine the total energy of an electron traveling at 0.98c. Hint: electron's rest energy = 0.51 MeV -0.25 MeV -1.8 MeV -0.51 MeV -2.6 MeV
2.6 MeV
A muon has rest energy 105 MeV. What is a muon's kinetic energy when its speed is 0.95c? 441 MeV 741 MeV 37 MeV 47 MeV 231 MeV
231 MeV
The surface of a metal plate is illuminated with light of a certain frequency. Which of the following conditions determine whether or not photoelectrons are ejected from the metal? 1. The number of photons per second emitted by the light source.2. The length of time that the light is turned on.3. The thermal conductivity of the metal.4. The surface area of the metal illuminated by the light.5. The type of metal from which the plate is made. 2 and 3 1 and 2 5 3 and 5 4
5
Rank the following nuclei in descending order (greatest first) according to density of each nucleus: C612, S50120n, P94239u. All the nuclei have approximately the same density. C612, S50120n, S50120n P94239u, S50120n, C612 S50120n, P94239u, C612 P94239u, C612, S50120n
All the nuclei have approximately the same density.
Which of the following quantities will two observers always measure to be the same, regardless of the relative velocity between the observers? -Both the speed of light in vacuum and the relative speed between observers. -The time interval between two events. -The speed of light in vacuum. -The length of an object. -The relative speed between the observers
Both the speed of light in vacuum and the relative speed between observers.
Which one of the following concepts explains why heavy nuclei do not follow the N = Z line (or trend) in the figure? -particle-wave duality -Coulomb repulsion -transmutation -Pauli exclusion principle -None of the above
Coulomb repulsion
Which one of the following statements is not part of the Bohr model of the atom? -Electrons move in circular orbits. -A photon is emitted when an electron drops from a higher energy orbit to a lower energy orbit. -The radii for Bohr orbits depends on the number of protons in the nucleus. -Electrons emit electromagnetic radiation as they orbit in stationary states. -The structure of the atom is that there is a very small, positively charged nucleus surrounded by electrons.
Electrons emit electromagnetic radiation as they orbit in stationary states.
Why was the observation of backscattered alpha particles so surprising to Rutherford in his experiment? -He thought alpha particles were waves that would simply be diffracted by the gold atoms -He realized that the positive charge must be concentrated in a very small region within the atom. -He was trying to produce lead from gold by using the alpha particles; and they weren't absorbed by the gold. -He was trying to produce flashes of light on a zinc sulfide screen; and there were none.
He realized that the positive charge must be concentrated in a very small region within the atom.
In the Bohr model of the hydrogen atom, the radius of the electron orbit increases by a factor of four. What happens to the magnitude of the orbital angular momentum of the electron? It doubles. It decreases by a factor of two. It decreases by a factor of four. It does not change. It increases by a factor of four.
It doubles.
Which series of lines in the hydrogen line spectrum involves electrons making a transition from higher energy levels down to the lowest energy level? -Paschen series -Pfund series -Brackett series -Lyman series -Balmer series
Lyman series
The drawing shows two sheets of polarizing material, which have their transmission axes crossed. The sheet on the left has its transmission axis aligned vertically. Light is incident from the left, as shown and can be either completely unpolarized or completely polarized along the vertical direction. Which one of the following statements is true concerning the light that exits the polarizer on the right? -Light exits the polarizer on the right for either the unpolarized or the polarized incident light. -No light exits the polarizer on the right for either the unpolarized or the polarized incident light. -Light exits the polarizer on the right for the polarized incident light, but not for the unpolarized incident light. -Light exits the polarizer on the right for the unpolarized incident light, but not for the polarized incident light.
No light exits the polarizer on the right for either the unpolarized or the polarized incident light.
An astronomer observes that the wavelength of light from a distant star is shifted toward the blue part of the visible spectrum. Which of the following is true? -The distance between the earth and the star is increasing -The distance between the earth and the star is remaining constant -The distance between the earth and the star is decreasing
The distance between the earth and the star is decreasing
A 90-watt red light bulb and a 60-watt green light bulb are turned on. Which bulb emits photons with the greater energy? The red bulb, because a red photon has a greater energy than a green photon. The green bulb, because a green photon has a greater energy than a red photon. The green bulb, because it emits more photons per second than the red bulb. The red bulb, because it emits more photons per second than the green bulb.
The green bulb, because a green photon has a greater energy than a red photon.
Which one of the following statements concerning the plum-pudding model of the atom is false? Negative electrons are dispersed uniformly within the positively charged "pudding" within the plum-pudding model atom. Positive charge is spread uniformly throughout the plum-pudding model atom. There is no nucleus at the center of the plum-pudding model atom. The plum-pudding model was proposed by Joseph J. Thomson. The plum-pudding model was proven correct in experiments by Ernest Rutherford.
The plum-pudding model was proven correct in experiments by Ernest Rutherford.
In a baseball game the batter hits the ball into center field and takes off for first base. The catcher can only stand and watch. Assume that the batter runs at a constant velocity. Who measures the proper time it takes for the runner to reach first base, and who measures the proper length between home plate and first base? The runner measures the proper time, and the catcher measures the proper length. The catcher measures the proper time, and the runner measures the proper length. The runner measures both the proper time and the proper length. The catcher measures both the proper time and the proper length.
The runner measures the proper time, and the catcher measures the proper length.
An X-ray photon with an initial wavelength λ strikes an electron that is initially at rest. Which one of the following statements best describes the wavelength of the photon after the collision? -The scattered photon's wavelength will still be λ, but its frequency will decrease. -The scattered photon's wavelength will be between λ/2 and λ -The scattered photon's wavelength will be λ/2. -No photon remains after the collision. -The scattered photon's wavelength will be longer than λ.
The scattered photon's wavelength will be longer than λ.
A space ship leaves the earth and travels to Alpha Centauri at a speed close to the speed of light. Passengers aboard the ship measure the distance from the earth to Alpha Centauri and the distance is also measure by scientists on earth. Which observers measure the proper length and which observer measures the shortest length? -The passengers measure the proper length and the passengers measure the shorter length. -The passengers measure the proper length and the scientists measure the shorter length. -The scientists measure the proper length and the passengers -measure the shorter length. -The passengers measure the proper length and all observers measure the same length. -The scientists measure the proper length and the scientists measure the shorter length.
The scientists measure the proper length and the passengers measure the shorter length.
What does the speed of light postulate state? -The speed of light in a vacuum is constant unless the viewer is moving toward or away from the light source. -The speed of light in a vacuum, measured in any inertial reference frame, always has the same value of c. -Nothing can travel faster than the speed of light. -The speed of light depends on the relative velocity of the light source relative to the observer. -The speed of light in a vacuum varies with the wavelength, but is a constant for each wavelength in all reference frames.
The speed of light in a vacuum, measured in any inertial reference frame, always has the same value of c.
Our bodies are mostly made of hydrogen (Z = 1), carbon (Z = 6), and oxygen (Z = 8). In our bodies, are there many more neutrons than protons, many fewer neutrons than protons, or are there about the same number of each? One cannot answer this question from the given information. There are many fewer neutrons than protons. There are about the same number of neutrons and protons. There are many more neutrons than protons.
There are about the same number of neutrons and protons.
If the speed of light were infinite, rather than c = 3.00 x 108 m/s, how would the classical momentum differ from the relativistic momentum? -The relativistic momentum would exceed the classical momentum. -The classical momentum would exceed the relativistic momentum. -There would be no difference between the momenta.
There would be no difference between the momenta.
What is the meaning of Einstein's famous equation E0 = mc2? -This represents the relativistic kinetic energy of an object of mass m. -This represents the energy equivalent of the mass of an object at rest. -This represents the energy equivalent of the mass of an object traveling at the speed of light. -This represents the total energy of an object of mass m. -This represents the maximum energy an object can have.
This represents the energy equivalent of the mass of an object at rest.
Which one of the following statements concerning time dilation is true? -Time dilation was demonstrated by the Michelson-Morley experiment. -Time dilation has been observed only in experiments involving radioactive decay processes. -Time dilation has been disproved in experiments with atomic clocks. -Time dilation has been observed in experiments involving both atomic clocks and radioactive decay processes. -Time dilation is predicted by special relativity, but has never been observed.
Time dilation has been observed in experiments involving both atomic clocks and radioactive decay processes.
Which one of the following statements about linear momentum is true (p = magnitude of the momentum, m = mass, and v = speed)? -When the magnitude p of the momentum is defined as p=mv1−v2/c2, the linear momentum of an isolated system is conserved only if the speeds of the various parts of the system are very high. -When the magnitude p of the momentum is defined as p = mv, the linear momentum of an isolated system is conserved only if the speeds of the various parts of the system are very high. -When the magnitude p of the momentum is defined as p=mv1−v2/c2, the linear momentum of an isolated system is conserved no matter what the speeds of the various parts of the system are. -When the magnitude p of the momentum is defined as p = mv, the linear momentum of an isolated system is conserved no matter what the speeds of the various parts of the system are.
When the magnitude p of the momentum is defined as p=mv1−v2/c2, the linear momentum of an isolated system is conserved no matter what the speeds of the various parts of the system are.
To which one of the following situations do the time-dilation and length-contraction equations apply? -With respect to an inertial frame, one observer has a constant velocity, and another observer has a constant acceleration. -With respect to an inertial frame, two observers have the same constant acceleration. -All of the above. -With respect to an inertial frame, two observers have different constant accelerations. -With respect to an inertial frame, two observers are moving with different constant velocities.
With respect to an inertial frame, two observers are moving with different constant velocities.
Which one of the following statements concerning electromagnetic waves is false? -X-rays have longer wavelengths than radio waves. -Electromagnetic waves carry energy. -They consist of mutually perpendicular electric and magnetic fields that oscillate perpendicular to the direction of propagation. -Lower frequency electromagnetic waves can be produced by oscillating circuits. -In vacuum, all electromagnetic waves travel at the same speed.
X-rays have longer wavelengths than radio waves.
Complete the following statement: The speed of light in a vacuum is -larger for short-wavelength electromagnetic waves. -larger for higher frequency electromagnetic waves. -smaller for higher energy electromagnetic waves. -larger for higher energy electromagnetic waves. -a constant value everywhere in the universe.
a constant value everywhere in the universe.
What type of particle is an alpha ray? -an electron -a helium nucleus -a photon -a neutron -a quark
a helium nucleus
Which one of the following will not generate electromagnetic waves or pulses? -an alternating current -a steady direct current -charged particles traveling in a circular path in a mass spectrometer -an accelerating electron -a proton in simple harmonic motion
a steady direct current
What term is used to describe the amount of energy required to break an atom apart? -radiation pressure -binding energy -work function -ionization energy -mass defect
binding energy
A ship is traveling away from you at a speed of 0.84c. A person fires a laser pulse at you from the back of the ship (i.e., at speed c relative to the ship). What speed do you measure for the speed of the laser pulse? -c -1.2c -0.8c -0.4c
c
Upon which one of the following parameters does the energy of a photon depend? polarization phase relationships mass frequency amplitude
frequency
Which one of the following types of nuclear radiation is not affected by a magnetic field? gamma rays helium nuclei β- rays β+ rays alpha particles
gamma rays
If both the electric and magnetic fields of an electromagnetic wave double in magnitude, how does the intensity of the wave change? The intensity -decreases by a factor of two. -decreases by a factor of four. -increases by a factor of two. -increases by a factor of four. -increases by a factor of eight.
increases by a factor of four.
Complete the following statement: The Michelson-Morley experiment -supported the relationship between mass and energy. -confirmed that time dilation occurs. -indicated that the speed of light is the same in all inertial reference frames. -verified the conservation of momentum in inertial reference frames. -proved that length contraction occurs.
indicated that the speed of light is the same in all inertial reference frames.
A nonrelativistic electron and a nonrelativistic proton are moving and have the same de Broglie wavelength. Which of the following are also the same for the two particles? -kinetic energy -frequency -speed -momentum
momentum
Space and time are intertwined when considering relativistic effects. Which of the following pairs are also intertwined for relativistic objects? -force and inertia -mass and kinetic energy -momentum and energy -linear and angular momenta -mass and momentum
momentum and energy
When vertically polarized light is incident on a sheet of polarizing material with a transmission axis oriented vertically, what percentage of the light is transmitted through the material? -fifty percent -one hundred percent -twenty-five percent -seventy-five percent -ten percent
one hundred percent
Which one of the following experiments provides evidence that light consists of particle-like entities? -crossed polarizers -Young's double-slit -photoelectric effect -Rutherford scattering -blackbody radiation
photoelectric effect
An electromagnetic wave is traveling in a vacuum. The magnitudes of the electric and magnetic fields of the wave are _____________, and the electric and magnetic energies carried by the wave are _____________. -proportional (but not equal) to each other, equal -equal, equal -proportional (but not equal) to each other, unequal -equal, proportional (but not equal) to each other
proportional (but not equal) to each other, equal
For which one of the following properties do visible light and ultraviolet waves have the same value? -wavelength -period -speed -frequency -energy
speed
The Compton effect illustrates __________ the wave nature of light. the ejection of photoelectrons when light strikes a metal surface. the Heisenberg uncertainty principle. that particle waves are waves of probability. the particle nature of light.
the particle nature of light.