Question 1

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

Accepted Answer

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

Question 2

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 3

The principle of Newtonian relativity predicts that

Accepted Answer

A) absolute motion can be detected. 
B) absolute motion cannot be detected. 
C) relative motion can be detected. 
D) relative motion cannot be detected. 
E) both absolute and relative motion can be detected. 
A) absolute motion can be detected. 
B) absolute motion cannot be detected. 
C) relative motion can be detected. 
D) relative motion cannot be detected. 
E) both absolute and relative motion can be detected.

Question 4

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 $\times$ 10-31 kg 
B) 9.11 $\times$ 10-31 kg 
C) 16.2 $\times$ 10-31 kg 
D) 5.90 $\times$ 10-31 kg 
E) infinite 
A) 12.3 $\times$ 10-31 kg 
B) 9.11 $\times$ 10-31 kg 
C) 16.2 $\times$ 10-31 kg 
D) 5.90 $\times$ 10-31 kg 
E) infinite

Question 5

Two electrons are ejected in opposite directions from atoms in a sample of radioactive material.Each electron has a speed,as measured by a laboratory observer,of 0.6c.What is the speed of one electron as seen from the other electron?

Accepted Answer

A) 0.361c 
B) 0.882c 
C) 1.87c 
D) zero 
E) 1.24c 
A) 0.361c 
B) 0.882c 
C) 1.87c 
D) zero 
E) 1.24c

Question 6

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 7

When a meterstick moves past you in the direction of its length,you measure it to be 90 cm long.What is its speed?

Accepted Answer

A) 5.7 $\times$ 107 m/s 
B) 9.5 $\times$ 107 m/s 
C) 1.3 $\times$ 108 m/s 
D) 2.4 $\times$ 108 m/s 
E) 2.7 $\times$ 108 m/s 
A) 5.7 $\times$ 107 m/s 
B) 9.5 $\times$ 107 m/s 
C) 1.3 $\times$ 108 m/s 
D) 2.4 $\times$ 108 m/s 
E) 2.7 $\times$ 108 m/s

Question 8

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 9

Our galaxy,the Milky Way,has a diameter of about 100 thousand light-years.How many years would it take a spacecraft to cross the galaxy if it could travel at 99% the speed of light?

Accepted Answer

A) 1.4 $\times$ 103 yrs 
B) 1.0 $\times$ 105 yrs 
C) 1.4 $\times$ 104 yrs 
D) 7.2 $\times$ 103 yrs 
E) None of these is correct. 
A) 1.4 $\times$ 103 yrs 
B) 1.0 $\times$ 105 yrs 
C) 1.4 $\times$ 104 yrs 
D) 7.2 $\times$ 103 yrs 
E) None of these is correct.

Question 10

The total yearly world consumption of energy is approximately 4.0 $\times$ 1020 J.How much mass would have to be completely converted into energy to provide this amount of energy?

Accepted Answer

A) 4.4 $\times$ 103 kg 
B) 1.3 $\times$ 1012 kg 
C) 1.3 $\times$ 104 kg 
D) 4.4 $\times$ 105 kg 
E) 2.2 $\times$ 104 kg 
A) 4.4 $\times$ 103 kg 
B) 1.3 $\times$ 1012 kg 
C) 1.3 $\times$ 104 kg 
D) 4.4 $\times$ 105 kg 
E) 2.2 $\times$ 104 kg

Question 11

Which of the following statement(s)is (are)a consequence of Einstein's postulates?

Accepted Answer

A) Every observer in every reference frame measures the same value for the speed of light. 
B) Moving clocks appear to run slow. 
C) Moving objects appear to be contracted along the direction of motion. 
D) Clocks synchronized in one reference frame are not synchronized in any frame moving relative to that reference frame. 
E) All of these are consequences of Einstein's postulates. 
A) Every observer in every reference frame measures the same value for the speed of light. 
B) Moving clocks appear to run slow. 
C) Moving objects appear to be contracted along the direction of motion. 
D) Clocks synchronized in one reference frame are not synchronized in any frame moving relative to that reference frame. 
E) All of these are consequences of Einstein's postulates.

Question 12

As an object of mass M approaches the speed of light,its momentum approaches

Accepted Answer

A) zero 
B) infinity 
C) Mc 
D) Mc2  
E) c 
A) zero 
B) infinity 
C) Mc 
D) Mc2  
E) c

Question 13

What is the momentum of an electron whose kinetic energy equals its rest mass,m?

Accepted Answer

A) 0.5 mc kg.m/s 
B)    kg.m/s 
C)    kg.m/s 
D)    kg.m/s 
E)    kg.m/s 
A) 0.5 mc kg.m/s 
B)    kg.m/s 
C)    kg.m/s 
D)    kg.m/s 
E)    kg.m/s

Question 14

You place two clocks that you consider to be synchronized on a road 100 m apart.Your friend drives by at speed V and observes the clocks to be out of sync by an amount T.When you place the clocks 200 m apart and your friend drives by at speed 2V,by what amount will your friend claim the clocks to be out of sync?

Accepted Answer

A) T 
B) 2T 
C) 4T 
D) T/2 
E) T/4 
A) T 
B) 2T 
C) 4T 
D) T/2 
E) T/4

Question 15

The light emitted by an object traveling at high speed toward Earth would

Accepted Answer

A) be shifted toward the blue end of the spectrum. 
B) be shifted toward the red end of the spectrum. 
C) undergo no spectral shifts. 
D) arrive with diminished intensity. 
E) None of these is correct. 
A) be shifted toward the blue end of the spectrum. 
B) be shifted toward the red end of the spectrum. 
C) undergo no spectral shifts. 
D) arrive with diminished intensity. 
E) None of these is correct.

Question 16

The linear momentum (p)times the speed of light (c)of an electron traveling at 0.98c is

Accepted Answer

A) 0.495 MeV 
B) 0.511 MeV 
C) 1.12 MeV 
D) 2.5 MeV 
E) 938 MeV 
A) 0.495 MeV 
B) 0.511 MeV 
C) 1.12 MeV 
D) 2.5 MeV 
E) 938 MeV

Question 17

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

Question 18

An electron traveling at 0.980c has a total energy of

Accepted Answer

A) 0.245 MeV 
B) 0.511 MeV 
C) 0.756 MeV 
D) 1.736 MeV 
E) 2.55 MeV 
A) 0.245 MeV 
B) 0.511 MeV 
C) 0.756 MeV 
D) 1.736 MeV 
E) 2.55 MeV

Question 19

Einstein's Second Postulate states that nothing can travel faster than the speed of light.The momentum of a particle of rest mass m

Accepted Answer

A) has an upper limit of mc. 
B) has an upper limit of 2mc. 
C) is infinite as the speed approaches c. 
D) has an upper limit of 0.5mc. 
E) none of the above 
A) has an upper limit of mc. 
B) has an upper limit of 2mc. 
C) is infinite as the speed approaches c. 
D) has an upper limit of 0.5mc. 
E) none of the above

Question 20

The expression relating the bending of the path of a relativistic,charged particle in a magnetic field to the particle's momentum is

Accepted Answer

A) p2 = 2mB 
B) p = qBr 
C) E2 = (pc)2 + E02 
D) p = q2B2r2/2m 
E)    
A) p2 = 2mB 
B) p = qBr 
C) E2 = (pc)2 + E02 
D) p = q2B2r2/2m 
E)

Exam 39: Relativity

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

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?

The principle of Newtonian relativity predicts that

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

Two electrons are ejected in opposite directions from atoms in a sample of radioactive material.Each electron has a speed,as measured by a laboratory observer,of 0.6c.What is the speed of one electron as seen from the other electron?

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

When a meterstick moves past you in the direction of its length,you measure it to be 90 cm long.What is its speed?

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

Our galaxy,the Milky Way,has a diameter of about 100 thousand light-years.How many years would it take a spacecraft to cross the galaxy if it could travel at 99% the speed of light?

The total yearly world consumption of energy is approximately 4.0 ×\times× 1020 J.How much mass would have to be completely converted into energy to provide this amount of energy?

Which of the following statement(s)is (are)a consequence of Einstein's postulates?

As an object of mass M approaches the speed of light,its momentum approaches

What is the momentum of an electron whose kinetic energy equals its rest mass,m?

The light emitted by an object traveling at high speed toward Earth would

The linear momentum (p)times the speed of light (c)of an electron traveling at 0.98c is

The kinetic energy of an electron traveling at 0.98c is

An electron traveling at 0.980c has a total energy of

Einstein's Second Postulate states that nothing can travel faster than the speed of light.The momentum of a particle of rest mass m

The expression relating the bending of the path of a relativistic,charged particle in a magnetic field to the particle's momentum is

Systems of Measurement

Motion in One Dimension

Motion in Two and Three Dimensions

Newtons Laws

Applications of Newtons Laws

Work and Energy

Conservation of Energy

Systems of Particles and Conservation of Linear Momentum

Rotation

Conservation of Angular Momentum

Gravity

Static Equilibrium and Elasticity

Fluids

Oscillations

Wave Motion

Superposition and Standing Waves

Temperature and the Kinetic Theory of Gases

Heat and the First Law of Thermodynamics

The Second Law of Thermodynamics

Thermal Properties and Processes

The Electric Field I: Discrete Charge Distributions

The Electric Field Ii: Continuous Charge Distributions

Electric Potential

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The Magnetic Field

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Alternating-Current Circuits

Maxwells Equations and Electromagnetic Waves

Properties of Light

Optical Images

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Wave Particle Duality and Quantum Physics

Applications of the Schrodinger Equation

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Elementary Particles and the Beginning of the Universe

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

The total yearly world consumption of energy is approximately 4.0 $\times$ 10²⁰ J.How much mass would have to be completely converted into energy to provide this amount of energy?