Exam 44: Particle Physics and Cosmology

If a galaxy is moving away from us at 1.0% of the speed of light,use Hubble's law to estimate how far away it is from us if the Hubble constant is 22 km/s per million light-years. ,1 ly = 9.461 × 10¹⁵ m,1 y = 3.156 × 10⁷ s)

Dark matter was initially proposed to explain

Is the decay Σ⁺ → p + π⁺ allowed?

Which one of the following decays CAN occur?

How many quarks are in a deuteron,²H?

Which one of the following processes CANNOT occur?

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

The H_α spectral line of hydrogen has a wavelength of 656.3 nm as measured in the laboratory.The H_α spectral line is observed in light from a distant star at a redshifted wavelength of 789.0 nm.If Hubble's law is valid for this star,estimate how far is it from Earth if the Hubble constant is 22 km/s per million light-years.(c = 3.00 × 10⁸ m/s, 1 ly=9.461 x 1015 m , 1 y = 3.156 × 10⁷ s)

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?

Is the decay π⁰ → μ⁺ + v_μ allowed?

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? , ,m_proton = 1.67 × 10^-27 kg)

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? ,

Composite particles that are composed of three quarks are called

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

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

Consider the decay π⁺ → μ⁺ + γ.This decay is

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

What is the quark composition of the proton?

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)

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