Exam 35: Interference

Hubble's law: Redshift measurements on a galaxy show that it is receding from us with a velocity of 7240 km/s. Estimate how far away the galaxy is 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)

Particles: A neutral η⁰ (having mass 0.642 u) that is at rest decays into two gamma ray photons. What is the energy in MeV of each photon? (1 u = 931.5 MeV/c²)

Cosmology: How long after the Big Bang did nucleosynthesis, the combining of protons and neutrons together to form nuclei, begin to occur?

Cosmology: Luminous (normal) matter makes up approximately what percentage of the known matter in the universe?

Particle accelerators: A cyclotron is designed with a magnet that produces a magnetic field of 1.2 T. When refurbished, the magnet is replaced by one that produces a 1.5-T field. How does the maximum kinetic energy achieved by the protons change compared to their previous maximum kinetic energy?

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

Hubble's law: If the Hubble constant is 25 km/s per million light-years, use it to estimate the age of the universe? (c = 3.00 × 10⁸ m/s, 1 ly = 9.461 × 10¹⁵ m, 1 y = 3.156 × 10⁷ s)

Particle accelerators: What type of particle accelerator has two large D-shaped electrodes with a small gap between them, through which an alternating potential difference accelerates the particles in a constant magnetic field?

Particle accelerators: The Large Hadron Collider (LHC) near Geneva, Switzerland is an example of a

Stars: If a spherical galaxy of diameter 100,000 ly contained enough mass to be a black hole having a Schwarzschild radius equal to that of the galaxy, what would be its mass? (G = 6.67 × 10^-11 N ∙ m²/kg², 1 ly = 9.461 × 10¹⁵ m, c = 3.00 × 10⁸ m/s)

Particles: Hadrons are divided into two subgroups called

Particle accelerators: A cyclotron of radius 0.25 m accelerates nonrelativistic protons in a 1.7-T magnetic field. What is the kinetic energy of the protons when they leave the cyclotron? (1 eV = 1.60 × 10^-19 J, e = 1.60 × 10^-19 C, m_proton = 1.67 × 10^-27 kg)

Conservation laws: The decay n → p⁺ + e^- + γ does not occur because it would violate conservation of

Hubble's law: A galaxy is observed receding from Earth with a speed of 9800 km/s. A redshifted spectral line originating in the galaxy is compared to the same spectral line originating in the laboratory. If Hubble's law is valid for this galaxy, what is the ratio of the wavelength of the redshifted line to that of the unshifted line 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)

Cosmology: The universe first became transparent to most light, coinciding with the origin of the cosmic background radiation, when the universe cooled enough to allow the formation of

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

Quarks: Composite particles that are composed of a quark and antiquark pair are called

Particles: Particles that do not interact via the strong force but do interact via the weak nuclear force (and presumably by the much weaker gravitation force) are called

Cosmology: The cosmic background radiation corresponds to a temperature of about

Cosmology: Dark matter was initially proposed to explain