Question 1

What is the momentum of a photon having the same total energy as an electron with a kinetic energy of 100 keV?

Accepted Answer

A)  zero 
B)  611 keV/c 
C)  100 keV/c 
D)  211 keV/c 
E)  411 keV/c 
A)  zero 
B)  611 keV/c 
C)  100 keV/c 
D)  211 keV/c 
E)  411 keV/c

Question 2

An astronaut aboard a spacecraft enroute to Mars with a speed of 0.5c relative to Earth observes a meteor approaching head on at a speed of 0.9c. What is the speed of the meteor relative to Earth?

Accepted Answer

A)  1.4c 
B)  -0.73c 
C)  0.4c 
D)  2.55c 
E)  None of these is correct. 
A)  1.4c 
B)  -0.73c 
C)  0.4c 
D)  2.55c 
E)  None of these is correct.

Question 3

The momentum of an electron moving at 0.8c is approximately

Accepted Answer

A)  0.511 MeV/c 
B)  1.02 MeV/c 
C)  2.18*10-22 kg · m/s 
D)  3.60 *10-22 kg · m/s 
E)  5.82 * 10-22 kg · m/s 
A)  0.511 MeV/c 
B)  1.02 MeV/c 
C)  2.18*10-22 kg · m/s 
D)  3.60 *10-22 kg · m/s 
E)  5.82 * 10-22 kg · m/s

Question 4

A proton that is being accelerated travels along arcs of a circle through the magnetic fields of a cyclotron. Near the beginning of its path through the cyclotron, the speed of the proton is slow and the radii of the arcs are small. Near the end of its path, the radii are large and the speed is c/3, so the motion of the particle must be treated relativistically. What must the ratio of the average magnetic field at the edge of the cyclotron to that at the center be to compensate for the relativistic momentum of the proton? HINT: The cyclotron frequency f = qB/2 $\pi$m must remain constant for the proton throughout its path.

Accepted Answer

A)  0.94 
B)  0.33 
C)  1.3 
D)  1.06 
E)  1.7 
A)  0.94 
B)  0.33 
C)  1.3 
D)  1.06 
E)  1.7

Question 5

Which of the following statements about an electron that is accelerated from rest through a potential difference of 150 kV is false?

Accepted Answer

A)  The kinetic energy of the electron is 1.5 *105 eV. 
B)  The value of e/m for the accelerated electron is greater than that of a slower electron. 
C)  The velocity of the electron is less than the velocity of light. 
D)  The relativistic mass of the electron is greater than its rest mass. 
E)  In the acceleration the electron will have gone from lower to higher potential. 
A)  The kinetic energy of the electron is 1.5 *105 eV. 
B)  The value of e/m for the accelerated electron is greater than that of a slower electron. 
C)  The velocity of the electron is less than the velocity of light. 
D)  The relativistic mass of the electron is greater than its rest mass. 
E)  In the acceleration the electron will have gone from lower to higher potential.

Question 6

Because the galaxies are moving away from us, the light they emit

Accepted Answer

A)  is shifted toward the shorter, blue wavelengths. 
B)  is shifted toward the longer, red wavelengths. 
C)  is of the same wavelength it would be if they were at rest relative to Earth. 
D)  arrives with increased intensity. 
E)  None of these is correct. 
A)  is shifted toward the shorter, blue wavelengths. 
B)  is shifted toward the longer, red wavelengths. 
C)  is of the same wavelength it would be if they were at rest relative to Earth. 
D)  arrives with increased intensity. 
E)  None of these is correct.

Question 7

An electron with a rest mass of 0.511 MeV travels at speed v = 0.500c. What is its kinetic energy?

Accepted Answer

A)  590 keV 
B)  80 keV 
C)  510 keV 
D)  430 keV 
E)  220 keV 
A)  590 keV 
B)  80 keV 
C)  510 keV 
D)  430 keV 
E)  220 keV

Question 8

The Sun radiates electromagnetic energy at the rate of 3.92 *1026 W. The mass of the Sun is 1.99 * 1030 kg. What fraction of the Sun's mass is lost during a human lifetime of 75 years?

Accepted Answer

A)  2.16 *10-13 
B)  1.42 *10-14 
C)  6.90 * 10-14 
D)  5.18 * 10-12 
E)  8.63 *10-14 
A)  2.16 *10-13 
B)  1.42 *10-14 
C)  6.90 * 10-14 
D)  5.18 * 10-12 
E)  8.63 *10-14

Question 9

How fast does an electron have to travel to have the same mass as a proton at rest?

Accepted Answer

A)  0.9985c 
B)  0.999985c 
C)  0.9999985c 
D)  0.99999985c 
E)  0.9999999985c 
A)  0.9985c 
B)  0.999985c 
C)  0.9999985c 
D)  0.99999985c 
E)  0.9999999985c

Question 10

Alpha Centauri is not only the closest star system to us (it is actually a triple star system) but it also seems to be an excellent place to look for extra-terrestrial life. It is about 4.3 light-years away from Earth. If an astronaut claims her journey there and back only took 6.3 years, then how fast was she traveling? (Assume she made a fast turnaround once she arrived there!)

Accepted Answer

A)  0.65c 
B)  0.73c 
C)  0.86c 
D)  0.81c 
E)  0.54c 
A)  0.65c 
B)  0.73c 
C)  0.86c 
D)  0.81c 
E)  0.54c

Question 11

An electron accelerated from rest through an electrostatic potential difference of 750 kV would have a total energy of approximately

Accepted Answer

A)  1.26 MeV 
B)  0.750 MeV 
C)  0.511 MeV 
D)  0.239 MeV 
E)  0.038 MeV 
A)  1.26 MeV 
B)  0.750 MeV 
C)  0.511 MeV 
D)  0.239 MeV 
E)  0.038 MeV

Question 12

A man standing on the platform of a railroad station observes two trains approaching him from opposite directions at speeds of 0.5c and 0.75c, respectively. At what speed does one train move with respect to the other?

Accepted Answer

A)  1.25c 
B)  0.25c 
C)  0.63c 
D)  0.91c 
E)  0.47c 
A)  1.25c 
B)  0.25c 
C)  0.63c 
D)  0.91c 
E)  0.47c

Question 13

A positron traveling at 50% the speed of light collides with an electron traveling at 75% the speed of light. The positron and electron annihilate. How much energy is released in MeV?

Accepted Answer

A)  1.36 MeV 
B)  0.182 MeV 
C)  1.022 MeV 
D)  0.892 MeV 
E)  1.53 MeV 
A)  1.36 MeV 
B)  0.182 MeV 
C)  1.022 MeV 
D)  0.892 MeV 
E)  1.53 MeV

Question 14

An electron is accelerated from rest by a total potential difference of 2.00 *108 V. Its mass at this energy is

Accepted Answer

A)  9.1 * 10-31 kg 
B)  2.27 *10-33 kg 
C)  1.67 * 10-27 kg 
D)  3.64 *10-28 kg 
E)  1.1 *10-16 kg 
A)  9.1 * 10-31 kg 
B)  2.27 *10-33 kg 
C)  1.67 * 10-27 kg 
D)  3.64 *10-28 kg 
E)  1.1 *10-16 kg

Question 15

An electron has 1022 keV of kinetic energy. What is its mass?

Accepted Answer

A)  9.11 *10-31 kg 
B)  1.82 * 10-30 kg 
C)  3.64 * 10-30 kg 
D)  4.56 * 10-31 kg 
E)  2.73 *10-30 kg 
A)  9.11 *10-31 kg 
B)  1.82 * 10-30 kg 
C)  3.64 * 10-30 kg 
D)  4.56 * 10-31 kg 
E)  2.73 *10-30 kg

Question 16

An earthbound radar monitors a spaceship moving at 0.9c that is being followed by a second ship moving at 0.8c. The second ship records the velocity of the faster ship as

Accepted Answer

A)  0.080c 
B)  0.10c 
C)  0.72c 
D)  0.36c 
E)  1.7c 
A)  0.080c 
B)  0.10c 
C)  0.72c 
D)  0.36c 
E)  1.7c

Question 17

Your strange friend flies past you in a relativistic spacecraft holding a meterstick and a clock. The meterstick appears too _____ to you, and the clock appears _____ to you.

Accepted Answer

A)  short; slow 
B)  long; slow 
C)  short; fast 
D)  long; fast 
E)  short; normal 
A)  short; slow 
B)  long; slow 
C)  short; fast 
D)  long; fast 
E)  short; normal

Question 18

Use the following scenario for the next question.
A 26-year-old biologist makes a trip to study alien life forms in a distant planet 10 light-years away. The round trip including a stay of 1 year in the distance planet takes 21.5 years according to the clock on earth. The biologist's son is 3-year-old when he left. Assume that the planet is not moving with respect to Earth, and the speed is the same for both outbound and inbound part of the journey.
-What is the total distance traveled according to the biologist? Give your answer in
Light-years.

Accepted Answer

A)  1.69 
B)  4.39 
C)  6.78 
D)  7.45 
E)  9.45 
A)  1.69 
B)  4.39 
C)  6.78 
D)  7.45 
E)  9.45

Question 19

If an electron, initially at rest, is accelerated through a potential difference of 180 kV, the relativistic mass of the electron is

Accepted Answer

A)  12.3*10-31 kg 
B)  9.11 * 10-31 kg 
C)  16.2 * 10-31 kg 
D)  5.90 * 10-31 kg 
E)  infinite 
A)  12.3*10-31 kg 
B)  9.11 * 10-31 kg 
C)  16.2 * 10-31 kg 
D)  5.90 * 10-31 kg 
E)  infinite

Question 20

The kinetic energy of an electron traveling at 0.98c is

Accepted Answer

A)  0.245 MeV 
B)  0.511 MeV 
C)  0.756 MeV 
D)  1.225 MeV 
E)  2.044 MeV 
A)  0.245 MeV 
B)  0.511 MeV 
C)  0.756 MeV 
D)  1.225 MeV 
E)  2.044 MeV

What is the momentum of a photon having the same total energy as an electron with a kinetic energy of 100 keV?

An astronaut aboard a spacecraft enroute to Mars with a speed of 0.5c relative to Earth observes a meteor approaching head on at a speed of 0.9c. What is the speed of the meteor relative to Earth?

The momentum of an electron moving at 0.8c is approximately

Which of the following statements about an electron that is accelerated from rest through a potential difference of 150 kV is false?

Because the galaxies are moving away from us, the light they emit

An electron with a rest mass of 0.511 MeV travels at speed v = 0.500c. What is its kinetic energy?

The Sun radiates electromagnetic energy at the rate of 3.92 10²⁶ W. The mass of the Sun is 1.99 10³⁰ kg. What fraction of the Sun's mass is lost during a human lifetime of 75 years?

How fast does an electron have to travel to have the same mass as a proton at rest?

An electron accelerated from rest through an electrostatic potential difference of 750 kV would have a total energy of approximately

A man standing on the platform of a railroad station observes two trains approaching him from opposite directions at speeds of 0.5c and 0.75c, respectively. At what speed does one train move with respect to the other?

A positron traveling at 50% the speed of light collides with an electron traveling at 75% the speed of light. The positron and electron annihilate. How much energy is released in MeV?

An electron is accelerated from rest by a total potential difference of 2.00 *10⁸ V. Its mass at this energy is

An electron has 1022 keV of kinetic energy. What is its mass?

An earthbound radar monitors a spaceship moving at 0.9c that is being followed by a second ship moving at 0.8c. The second ship records the velocity of the faster ship as

Your strange friend flies past you in a relativistic spacecraft holding a meterstick and a clock. The meterstick appears too _ to you, and the clock appears _ to you.

If an electron, initially at rest, is accelerated through a potential difference of 180 kV, the relativistic mass of the electron is

The kinetic energy of an electron traveling at 0.98c is

The Electric Field I: Discrete Charge Distributions

The Electric Field II: Continuous Charge Distributions

Electric Potential

Capacitance

Electric Current and Direct-Current Circuits

The Magnetic Field

Sources of the Magnetic Field

Magnetic Induction

Alternating-Current Circuits

Maxwells Equations and Electromagnetic Waves

Properties of Light

Optical Images

Interference and Diffraction

Wave Particle Duality and Quantum Physics

Applications of the Schrodinger Equation

Atoms

Molecules

Solids and the Theory of Conduction

Nuclear Physics

Elementary Particles and the Beginning of the Universe

Filters

Exam 19: Relativity

What is the momentum of a photon having the same total energy as an electron with a kinetic energy of 100 keV?

An astronaut aboard a spacecraft enroute to Mars with a speed of 0.5c relative to Earth observes a meteor approaching head on at a speed of 0.9c. What is the speed of the meteor relative to Earth?

The momentum of an electron moving at 0.8c is approximately

Which of the following statements about an electron that is accelerated from rest through a potential difference of 150 kV is false?

Because the galaxies are moving away from us, the light they emit

An electron with a rest mass of 0.511 MeV travels at speed v = 0.500c. What is its kinetic energy?

The Sun radiates electromagnetic energy at the rate of 3.92 *1026 W. The mass of the Sun is 1.99 * 1030 kg. What fraction of the Sun's mass is lost during a human lifetime of 75 years?

How fast does an electron have to travel to have the same mass as a proton at rest?

An electron accelerated from rest through an electrostatic potential difference of 750 kV would have a total energy of approximately

A man standing on the platform of a railroad station observes two trains approaching him from opposite directions at speeds of 0.5c and 0.75c, respectively. At what speed does one train move with respect to the other?

A positron traveling at 50% the speed of light collides with an electron traveling at 75% the speed of light. The positron and electron annihilate. How much energy is released in MeV?

An electron is accelerated from rest by a total potential difference of 2.00 *108 V. Its mass at this energy is

An electron has 1022 keV of kinetic energy. What is its mass?

An earthbound radar monitors a spaceship moving at 0.9c that is being followed by a second ship moving at 0.8c. The second ship records the velocity of the faster ship as

Your strange friend flies past you in a relativistic spacecraft holding a meterstick and a clock. The meterstick appears too _____ to you, and the clock appears _____ to you.

If an electron, initially at rest, is accelerated through a potential difference of 180 kV, the relativistic mass of the electron is

The kinetic energy of an electron traveling at 0.98c is

The Electric Field I: Discrete Charge Distributions

The Electric Field II: Continuous Charge Distributions

Electric Potential

Capacitance

Electric Current and Direct-Current Circuits

The Magnetic Field

Sources of the Magnetic Field

Magnetic Induction

Alternating-Current Circuits

Maxwells Equations and Electromagnetic Waves

Properties of Light

Optical Images

Interference and Diffraction

Wave Particle Duality and Quantum Physics

Applications of the Schrodinger Equation

Atoms

Molecules

Solids and the Theory of Conduction

Nuclear Physics

Elementary Particles and the Beginning of the Universe

Filters

The Sun radiates electromagnetic energy at the rate of 3.92 10²⁶ W. The mass of the Sun is 1.99 10³⁰ kg. What fraction of the Sun's mass is lost during a human lifetime of 75 years?

An electron is accelerated from rest by a total potential difference of 2.00 *10⁸ V. Its mass at this energy is

Your strange friend flies past you in a relativistic spacecraft holding a meterstick and a clock. The meterstick appears too _ to you, and the clock appears _ to you.