Question 1

Conservation laws: Is the decay Σ+ → p + π+ allowed?

Accepted Answer

A)  Yes, because it conserves energy. 
B)  No, because charge is not conserved. 
C)  No, because mass is created. 
D)  No, because lepton number is not conserved. 
A)  Yes, because it conserves energy. 
B)  No, because charge is not conserved. 
C)  No, because mass is created. 
D)  No, because lepton number is not conserved.

Question 2

Hubble's law: Estimate the speed of a galaxy away from us if it is 10 billion light-years from us and if the Hubble constant is 22 km/s per million light-years. (c = 3.00 × 108 m/s, 1 ly = 9.461 × 1015 m, 1 y = 3.156 × 107 s)

Accepted Answer

A)  0.1c 
B)  0.3c 
C)  0.5c 
D)  0.7c 
E)  0.9c 
A)  0.1c 
B)  0.3c 
C)  0.5c 
D)  0.7c 
E)  0.9c

Question 3

Stars: The sun has apparent brightness B when observed from Earth, 1.5 × 108 km away. What would be the apparent brightness of the sun viewed from Pluto, which is 6.0 × 109 km from the sun?

Accepted Answer

A)  0.50B 
B)  0.25B 
C)  0.063B 
D)  0.025B 
E)  0.00063B 
A)  0.50B 
B)  0.25B 
C)  0.063B 
D)  0.025B 
E)  0.00063B

Question 4

Particles: Which of the following particles are leptons? (There may be more than one correct choice.)

Accepted Answer

A)  positron 
B)  muon 
C)  π-meson 
D)  neutron 
E)  electron 
A)  positron 
B)  muon 
C)  π-meson 
D)  neutron 
E)  electron

Question 5

Quarks: How many quarks are in a deuteron, 2H?

Accepted Answer

A)  1 
B)  2 
C)  3 
D)  4 
E)  6 
A)  1 
B)  2 
C)  3 
D)  4 
E)  6

Question 6

Conservation laws: Which one of the following decays CAN occur?

Accepted Answer

A)  π+ → μ+ + vμ 
B)  p + n → p + p +   
C)  K+ → π0 
D)  μ- → e- + ve + vμ 
E)  K+ → 2π0 
A)  π+ → μ+ + vμ 
B)  p + n → p + p +   
C)  K+ → π0 
D)  μ- → e- + ve + vμ 
E)  K+ → 2π0

Question 7

Hubble's law: A distant galaxy is emitting light from the helium spectrum at 388.9 nm. On Earth the wavelength of the light from this galaxy is measured to be 540.6 nm. Estimate how far from Earth (in light-years) this galaxy is if the Hubble constant has the value 22 km/s per million light-years. (c = 3.00 × 108 m/s, 1 ly = 9.461 × 1015 m, 1 y = 3.156 × 107 s)

Accepted Answer

Question 8

Hubble's law: If a galaxy is receding from us at 0.10c. Use Hubble's law to estimate the distance to this galaxy if the Hubble constant is 22 km/s per million light-years. (c = 3.00 × 108 m/s, 1 ly = 9.461 × 1015 m, 1 y = 3.156 × 107 s)

Accepted Answer

A)  1.4 × 109 ly 
B)  6.6 × 105 ly 
C)  6.6 × 105 Mly 
D)  2.2 Mly 
E)  1.4 × 107 Mly 
A)  1.4 × 109 ly 
B)  6.6 × 105 ly 
C)  6.6 × 105 Mly 
D)  2.2 Mly 
E)  1.4 × 107 Mly

Question 9

Particles: Suppose you were to try to create a proton-antiproton pair by annihilation of two very high-energy gamma rays of the same wavelength heading toward each other. The proton and the anti-proton have the same masses, but opposite charges. What would be the minimum energy needed for each photon? (e = 1.60 × 10-19 C, mproton = 1.67 × 10-27 kg, c = 3.00 × 108 m/s)

Accepted Answer

A)  1.022 MeV 
B)  12.2 MeV 
C)  1880 MeV 
D)  939 MeV 
E)  223 MeV 
A)  1.022 MeV 
B)  12.2 MeV 
C)  1880 MeV 
D)  939 MeV 
E)  223 MeV

Question 10

Particle accelerators: A cyclotron of radius 0.25 m accelerates protons in a 1.7-T magnetic field. What is the frequency for the applied alternating voltage? (mproton = 1.67 × 10-27 kg, e = 1.60 × 10-19C)

Accepted Answer

A)  0.26 MHz 
B)  2.6 MHz 
C)  26 MHz 
D)  260 MHz 
A)  0.26 MHz 
B)  2.6 MHz 
C)  26 MHz 
D)  260 MHz

Question 11

Particles: What type of particle is an electron? (There may be more than one correct choice.)

Accepted Answer

A)  lepton 
B)  meson 
C)  baryon 
D)  nucleon 
E)  hadron 
A)  lepton 
B)  meson 
C)  baryon 
D)  nucleon 
E)  hadron

Question 12

Stars: A star has absolute luminosity equal to that of the sun, which is 1.5 × 108 km from the earth, but this star is 32.6 light-years away from the earth. By what factor will it appear dimmer than the sun? (1 ly = 9.461 × 1015 m)

Accepted Answer

A)  2.4 × 10-9 
B)  2.4 × 10-11 
C)  2.4 × 10-13 
D)  2.4 × 10-15 
E)  2.4 × 10-17 
A)  2.4 × 10-9 
B)  2.4 × 10-11 
C)  2.4 × 10-13 
D)  2.4 × 10-15 
E)  2.4 × 10-17

Question 13

Conservation laws: Is the decay π0 → μ+ + vμ allowed?

Accepted Answer

A)  Yes, because it conserves energy. 
B)  No, because charge is not conserved. 
C)  No, because mass is created. 
D)  No, because lepton number is not conserved. 
A)  Yes, because it conserves energy. 
B)  No, because charge is not conserved. 
C)  No, because mass is created. 
D)  No, because lepton number is not conserved.

Question 14

Stars: What is the parallax angle for Proxima Centauri, which is Earth's nearest star at 4.3 ly? Earth's orbit around the sun has a mean radius of 1.5 × 108 km, and 1 ly = 9.461 × 1015 m.

Accepted Answer

A)  1.2 × 10-14 degree 
B)  2.1 × 10-4 degree 
C)  1.2 × 10-7 degree 
D)  2.1 × 10-7 degree 
E)  2.1 × 10-14 degree 
A)  1.2 × 10-14 degree 
B)  2.1 × 10-4 degree 
C)  1.2 × 10-7 degree 
D)  2.1 × 10-7 degree 
E)  2.1 × 10-14 degree

Question 15

Hubble's law: A giant star in another galaxy exploded 67 million years ago, forming a supernova. The event is observed by an astronomer on Earth. Estimate the speed at which the supernova (and its galaxy) recedes from Earth if the Hubble constant is 22 km/s per million light-years. (c = 3.00 × 108 m/s, 1 ly = 9.461 × 1015 m, 1 y = 3.156 × 107 s)

Accepted Answer

A)  1200 km/s 
B)  670 km/s 
C)  1500 km/s 
D)  2700 km/s 
E)  4700 km/s 
A)  1200 km/s 
B)  670 km/s 
C)  1500 km/s 
D)  2700 km/s 
E)  4700 km/s

Question 16

Cosmology: Dark energy accounts for what percent of the known energy in the universe?

Accepted Answer

A)  8% 
B)  24% 
C)  68% 
D)  94% 
A)  8% 
B)  24% 
C)  68% 
D)  94%

Question 17

Quarks: Given that the reaction n + π+ → p can occur and that the quark composition of the neutron is udd and that of the proton is uud, what must be the quark composition of the π+ meson?

Accepted Answer

A)  u   
B)    d 
C)  d   
D)  u   
E)    d
  
A)  u   
B)    d 
C)  d   
D)  u   
E)    d

Question 18

Cosmology: Suppose that the Hubble constant had the value 35.0 km/s per million light-years. (1 y = 3.156 × 107 s, mH ≈ mproton = 1.67 × 10-27 kg, c = 3.00 × 108 m/s, 1 light-year = 9.461 × 1015 m, G = 6.67 × 10-11 N ∙ m2/kg2)
(a) What would be the maximum density the universe could have that would still allow it to expand forever?
(b) Under the conditions of part (a), how many hydrogen atoms would we expect to find, on the average, in a volume of space measuring 3.00 m by 8.00 m by 8.00 m?

Accepted Answer

(a) 2.45 ×

Question 19

Particle accelerators: A deuteron has the same charge as a proton but approximately twice the proton mass. Suppose deuterons are being accelerated in a cyclotron in an orbit of radius 75 cm at a frequency of 8.0 MHz. What magnetic field magnitude is needed? (e = 1.60 × 10-19 C, mproton = 1.67 × 10-27 kg)

Accepted Answer

A)  0.011 T 
B)  0.11 T 
C)  1.1 T 
D)  11 T 
E)  110 T 
A)  0.011 T 
B)  0.11 T 
C)  1.1 T 
D)  11 T 
E)  110 T

Question 20

Conservation laws: The reaction p + e- → + e+ is not possible because

Accepted Answer

A)  baryon number is not conserved. 
B)  lepton number is not conserved. 
C)  charge is not conserved. 
D)  energy is not conserved. 
E)  This reaction IS possible. 
A)  baryon number is not conserved. 
B)  lepton number is not conserved. 
C)  charge is not conserved. 
D)  energy is not conserved. 
E)  This reaction IS possible.

Exam 35: Interference

Conservation laws: Is the decay Σ+ → p + π+ allowed?

Hubble's law: Estimate the speed of a galaxy away from us if it is 10 billion light-years from us and if the Hubble constant is 22 km/s per million light-years. (c = 3.00 × 108 m/s, 1 ly = 9.461 × 1015 m, 1 y = 3.156 × 107 s)

Stars: The sun has apparent brightness B when observed from Earth, 1.5 × 108 km away. What would be the apparent brightness of the sun viewed from Pluto, which is 6.0 × 109 km from the sun?

Particles: Which of the following particles are leptons? (There may be more than one correct choice.)

Quarks: How many quarks are in a deuteron, 2H?

Conservation laws: Which one of the following decays CAN occur?

Hubble's law: If a galaxy is receding from us at 0.10c. Use Hubble's law to estimate the distance to this galaxy if the Hubble constant is 22 km/s per million light-years. (c = 3.00 × 108 m/s, 1 ly = 9.461 × 1015 m, 1 y = 3.156 × 107 s)

Particle accelerators: A cyclotron of radius 0.25 m accelerates protons in a 1.7-T magnetic field. What is the frequency for the applied alternating voltage? (mproton = 1.67 × 10-27 kg, e = 1.60 × 10-19C)

Particles: What type of particle is an electron? (There may be more than one correct choice.)

Stars: A star has absolute luminosity equal to that of the sun, which is 1.5 × 108 km from the earth, but this star is 32.6 light-years away from the earth. By what factor will it appear dimmer than the sun? (1 ly = 9.461 × 1015 m)

Conservation laws: Is the decay π0 → μ+ + vμ allowed?

Stars: What is the parallax angle for Proxima Centauri, which is Earth's nearest star at 4.3 ly? Earth's orbit around the sun has a mean radius of 1.5 × 108 km, and 1 ly = 9.461 × 1015 m.

Cosmology: Dark energy accounts for what percent of the known energy in the universe?

Quarks: Given that the reaction n + π+ → p can occur and that the quark composition of the neutron is udd and that of the proton is uud, what must be the quark composition of the π+ meson?

Conservation laws: The reaction p + e- → + e+ is not possible because

Motion Along a Straight Line

Motion in Two or Three Dimensions

Newtons Laws of Motion

Applying Newtons Laws

Work and Kinetic Energy

Potential Energy and Energy Conservation

Momentum, Impulse, and Collisions

Rotation of Rigid Bodies

Dynamics of Rotational Motion

Equilibrium and Elasticity

Fluid Mechanics

Gravitation

Periodic Motion

Mechanical Waves

Sound and Hearing

Temperature and Heat

Thermal Properties of Matter

The First Law of Thermodynamics

The Second Law of Thermodynamics

Electric Charge and Electric Field

Gausss Law

Electric Potential

Capacitance and Dielectrics

Current, Resistance, and Electromotive Force

Direct-Current Circuits

Magnetic Field and Magnetic Forces

Sources of Magnetic Field

Electromagnetic Induction

Inductance

Alternating Current

Electromagnetic Waves Optics

The Nature and Propagation of Light

Geometric Optics

Filters

Conservation laws: Is the decay Σ⁺ → p + π⁺allowed?

Hubble's law: Estimate the speed of a galaxy away from us if it is 10 billion light-years from us and if the Hubble constant is 22 km/s per million light-years. (c = 3.00 × 10⁸ m/s, 1 ly = 9.461 × 10¹⁵ m, 1 y = 3.156 × 10⁷ s)

Stars: The sun has apparent brightness B when observed from Earth, 1.5 × 10⁸ km away. What would be the apparent brightness of the sun viewed from Pluto, which is 6.0 × 10⁹ km from the sun?

Quarks: How many quarks are in a deuteron, ²H?

Hubble's law: If a galaxy is receding from us at 0.10c. Use Hubble's law to estimate the distance to this galaxy if the Hubble constant is 22 km/s per million light-years. (c = 3.00 × 10⁸ m/s, 1 ly = 9.461 × 10¹⁵ m, 1 y = 3.156 × 10⁷ s)

Particle accelerators: A cyclotron of radius 0.25 m accelerates protons in a 1.7-T magnetic field. What is the frequency for the applied alternating voltage? (m_proton = 1.67 × 10^-27 kg, e = 1.60 × 10^-19C)

Stars: A star has absolute luminosity equal to that of the sun, which is 1.5 × 10⁸ km from the earth, but this star is 32.6 light-years away from the earth. By what factor will it appear dimmer than the sun? (1 ly = 9.461 × 10¹⁵ m)

Conservation laws: Is the decay π⁰ → μ⁺ + v_μ allowed?

Stars: What is the parallax angle for Proxima Centauri, which is Earth's nearest star at 4.3 ly? Earth's orbit around the sun has a mean radius of 1.5 × 10⁸ km, and 1 ly = 9.461 × 10¹⁵ m.

Quarks: Given that the reaction n + π⁺ → p can occur and that the quark composition of the neutron is udd and that of the proton is uud, what must be the quark composition of the π⁺ meson?

Conservation laws: The reaction p + e^- → + e+ is not possible because