Exam 30: Quantum Physics

A beam of light with a frequency range of 3.01 × 10¹⁴ Hz - 6.10 × 10¹⁴ Hz is incident on a metal surface. If the work function of the metal surface is 2.20 eV, what is the range of frequencies in this beam of light that will be responsible for ejecting electrons from this metal surface?

A zero value for the Planck's constant would mean that the laws of classical physics would apply to quantum physics.

The excited state of a certain atom is 3.2 eV ± 0.21 eV. (a) What is the average lifetime of this state? (b) If the excited energy doubled (6.4 eV ± 0.21 eV) how would the lifetime be affected?

A proton and an electron are both accelerated to the same final kinetic energy. If λ_p is the de Broglie wavelength of the proton and λ_e is the de Broglie wavelength of the electron, then

The momentum of a photon is inversely proportional to its total energy.

Atoms in crystals are typically separated by distances of 0.10 nm. What KE must an electron have, in eV, in order to have a wavelength of 0.10 nm?

What scattering angle in the Compton effect produces the minimum change in frequency?

What is the surface temperature of a star, given that its radiation peak occurs at a frequency of 1.06 × 10¹⁵ Hz?

Unlike other particles, photons have a finite momentum even though they have no mass.

How "slow" must a 200. gram ball move to have a deBroglie wavelength of 1.0 mm?

Protons are being accelerated in a particle accelerator. When the energy of the protons is doubled, their de Broglie wavelength will

An electron is known to be confined to a region of width 0.10 nm. What is an approximate expression for the least kinetic energy it could have, expressed in eV?

X-rays with a wavelength of 0.00100 nm are scattered by free electrons at 130°. What is the kinetic energy of each recoil electron?

A proton, moving freely, has a wavelength of 0.600 pm. (a) What is its momentum? (b) What is its speed? (c) Through what potential difference might it have been accelerated through, from rest, to reach this speed?

The surface temperature of the star is 6000 K. What is the wavelength associated with the light emitted by this star?

If a beam of X-rays is scattered from protons instead of electrons, the change in the wavelength of this X-ray beam for a given angle of scattering decreases.

What happens to the frequency of the scattered X-rays beam as the scattering angle in the Compton effect decreases?

A certain crystal has an interatomic spacing of 0.442 nm. A beam of neutrons moving with a speed of 1640 m/s is diffracted from the crystal. What is the angle of the second interference maximum?

The de Broglie wavelength of an electron is 380 nm. What is the speed of this electron?

The energy of an ultraviolet photon is more than the energy of an infrared photon.