Question 1

A neutron cannot decay into a neutrino and an antineutrino. This decay would violate baryon number conservation and which other conservation law?

Accepted Answer

A)  Energy 
B)  Lepton number 
C)  Electric charge 
D)  Linear momentum 
E)  Angular momentum 
A)  Energy 
B)  Lepton number 
C)  Electric charge 
D)  Linear momentum 
E)  Angular momentum

Question 2

The mass of the W boson is 80 GeV/c2. During beta decay, a virtual W is created. In order not to visibly violate conservation of energy, what is the longest time the W particle can be in existence?

Accepted Answer

A)  0 s 
B)  8 x 10-45 s 
C)  8 x 10-36 s 
D)  8 x 10-27 s 
E)  There is no limit on the time the W can exist. 
A)  0 s 
B)  8 x 10-45 s 
C)  8 x 10-36 s 
D)  8 x 10-27 s 
E)  There is no limit on the time the W can exist.

Question 3

A galaxy 200 Mpc from us has a recessional velocity of about 14,000 km/s. If it emits radiation at a wavelength of 121 nm, how much is that wavelength shifted when we observe it?

Accepted Answer

A)  5.7 x 10-12 m 
B)  5.7 x 10-10 m 
C)  5.7 x 10-9 m 
D)  5.7 x 10-7 m 
E)  5.7 x 10-6 m 
A)  5.7 x 10-12 m 
B)  5.7 x 10-10 m 
C)  5.7 x 10-9 m 
D)  5.7 x 10-7 m 
E)  5.7 x 10-6 m

Question 4

An electron participates in:

Accepted Answer

A)  the electromagnetic and weak forces only 
B)  the strong and weak forces only 
C)  the electromagnetic and gravitational forces only 
D)  the electromagnetic, gravitational, and weak forces only 
E)  the electromagnetic, gravitational, and strong forces only 
A)  the electromagnetic and weak forces only 
B)  the strong and weak forces only 
C)  the electromagnetic and gravitational forces only 
D)  the electromagnetic, gravitational, and weak forces only 
E)  the electromagnetic, gravitational, and strong forces only

Question 5

Objects in the universe are receding from us with a speed that is proportional to:

Accepted Answer

A)  the reciprocal of the square of their distance from us 
B)  the reciprocal of their distance from us 
C)  their distance from us 
D)  the square of their distance from us 
E)  their distance from the center of the universe 
A)  the reciprocal of the square of their distance from us 
B)  the reciprocal of their distance from us 
C)  their distance from us 
D)  the square of their distance from us 
E)  their distance from the center of the universe

Question 6

A particle with spin angular momentum is called a:

Accepted Answer

A)  lepton 
B)  hadron 
C)  fermion 
D)  boson 
E)  electron 
A)  lepton 
B)  hadron 
C)  fermion 
D)  boson 
E)  electron

Question 7

If dark matter did not exist it is likely that:

Accepted Answer

A)  the universe would expand forever 
B)  the universe would begin contracting soon 
C)  the night sky would be brighter 
D)  the night sky would be darker 
E)  we would be able to see the center of the universe 
A)  the universe would expand forever 
B)  the universe would begin contracting soon 
C)  the night sky would be brighter 
D)  the night sky would be darker 
E)  we would be able to see the center of the universe

Question 8

Color is carried by:

Accepted Answer

A)  only quarks 
B)  only leptons 
C)  only quarks and leptons 
D)  only quarks and gluons 
E)  only photons and gluons 
A)  only quarks 
B)  only leptons 
C)  only quarks and leptons 
D)  only quarks and gluons 
E)  only photons and gluons

Question 9

A baryon with strangeness -1 decays via the strong interaction into two particles, one of which is a baryon with strangeness 0. The other is:

Accepted Answer

A)  a baryon with strangeness 0 
B)  a baryon with strangeness +1 
C)  a meson with strangeness -1 
D)  a meson with strangeness +1 
E)  a meson with strangeness 0 
A)  a baryon with strangeness 0 
B)  a baryon with strangeness +1 
C)  a meson with strangeness -1 
D)  a meson with strangeness +1 
E)  a meson with strangeness 0

Question 10

A particle with spin angular momentum is called a:

Accepted Answer

A)  lepton 
B)  hadron 
C)  fermion 
D)  boson 
E)  electron 
A)  lepton 
B)  hadron 
C)  fermion 
D)  boson 
E)  electron

Question 11

The intensity of the microwave background radiation, a remnant of the big bang:

Accepted Answer

A)  is greatest in directions toward the center of the galaxy 
B)  is least in directions toward the center of the galaxy 
C)  is proportional to the reciprocal of the distance from us 
D)  is proportional to the square of the distance from us 
E)  is nearly the same in all directions 
A)  is greatest in directions toward the center of the galaxy 
B)  is least in directions toward the center of the galaxy 
C)  is proportional to the reciprocal of the distance from us 
D)  is proportional to the square of the distance from us 
E)  is nearly the same in all directions

Question 12

A down quark can be changed into an up quark (plus other particles perhaps) by:

Accepted Answer

A)  the gravitational interaction 
B)  the weak interaction 
C)  the electromagnetic interaction 
D)  the strong interaction 
E)  none of these 
A)  the gravitational interaction 
B)  the weak interaction 
C)  the electromagnetic interaction 
D)  the strong interaction 
E)  none of these

Question 13

Different types of neutrinos can be distinguished from each other by:

Accepted Answer

A)  the directions of their spins 
B)  the leptons with which they interact 
C)  the baryons with which they interact 
D)  the number of photons that accompany them 
E)  their baryon numbers 
A)  the directions of their spins 
B)  the leptons with which they interact 
C)  the baryons with which they interact 
D)  the number of photons that accompany them 
E)  their baryon numbers

Question 14

How many different flavors of quarks are there (not counting antiquarks)?

Accepted Answer

A)  1 
B)  3 
C)  6 
D)  12 
E)  18 
A)  1 
B)  3 
C)  6 
D)  12 
E)  18

Question 15

The velocities of distant objects in the universe indicate that the time elapsed since the big bang is about:

Accepted Answer

A)  105 y 
B)  1010 y 
C)  1015 y 
D)  1020 y 
E)  1025 y 
A)  105 y 
B)  1010 y 
C)  1015 y 
D)  1020 y 
E)  1025 y

Exam 44: Quarks, Leptons, and the Big Bang

A neutron cannot decay into a neutrino and an antineutrino. This decay would violate baryon number conservation and which other conservation law?

The mass of the W boson is 80 GeV/c2. During beta decay, a virtual W is created. In order not to visibly violate conservation of energy, what is the longest time the W particle can be in existence?

A galaxy 200 Mpc from us has a recessional velocity of about 14,000 km/s. If it emits radiation at a wavelength of 121 nm, how much is that wavelength shifted when we observe it?

An electron participates in:

Objects in the universe are receding from us with a speed that is proportional to:

A particle with spin angular momentum is called a:

If dark matter did not exist it is likely that:

Color is carried by:

A baryon with strangeness -1 decays via the strong interaction into two particles, one of which is a baryon with strangeness 0. The other is:

A particle with spin angular momentum is called a:

The intensity of the microwave background radiation, a remnant of the big bang:

A down quark can be changed into an up quark (plus other particles perhaps) by:

Different types of neutrinos can be distinguished from each other by:

How many different flavors of quarks are there (not counting antiquarks)?

The velocities of distant objects in the universe indicate that the time elapsed since the big bang is about:

Measurement

Motion Along a Straight Line

Vector

Motion in Two and Three Dimensions

Force and Motion I

Force and Motion II

Kinetic Energy and Work

Potential Energy and Conservation of Energy

Center of Mass and Linear Momentum

Rotation

Rolling, Torque, and Angular Momentum

Equilibrium and Elasticity

Gravitation

Fluids

Oscillations

Waves I

Waves II

Temperature, Heat, and the First Law of Thermodynamics

The Kinetic Theory of Gases

Entropy and the Second Law of Thermodynamics

Electric Charge

Electric Fields

Gauss Law

Electric Potential

Capacitance

Current and Resistance

Circuits

Magnetic Fields

Magnetic Fields Due to Currents

Induction and Inductance

Electromagnetic Oscillations and Alternating Current

Maxwells Equations; Magnetism of Matter

Electromagnetic Waves

Images

Interference

Diffraction

Relativity

Photons and Matter Waves

More About Matter Waves

All About Atoms

Conduction of Electricity in Solids

Nuclear Physics

Energy From the Nucleus

Filters

The mass of the W boson is 80 GeV/c². During beta decay, a virtual W is created. In order not to visibly violate conservation of energy, what is the longest time the W particle can be in existence?