Modern Physics Test. 1

The relationship is given by the formula E = hf, where 'h' is Planck's constant. Energy is directly proportional to frequency.

Planck's fundamental postulate is that energy is quantized, meaning it is emitted or absorbed in discrete packets (quanta), resolving the ultraviolet catastrophe.

Binding energy per nucleon = Total binding energy / number of nucleons = 1786 MeV / 235 = 7.6 MeV.

Davisson and Germer observed that a beam of electrons scattered by a nickel crystal produced a diffraction pattern, which is a definitive characteristic of waves.

The photon transfers some of its energy to the electron. Since energy and wavelength are inversely related (E = hc/λ), a decrease in energy results in an increase in wavelength.

Pair annihilation occurs when a particle and its antiparticle (e.g., electron and positron) collide, converting their mass back into energy, typically in the form of two photons.

Number of half-lives = 20,000 years / 5000 years = 4. The fraction remaining is (1/2) to the power of 4, which is 1/16.

An ideal black body is defined as a body that absorbs all incident radiation and is also a perfect emitter of radiation, with the emission spectrum depending only on its temperature.

The photon's energy must be at least equal to the sum of the rest mass energies of the electron (0.51 MeV) and the positron (0.51 MeV), totaling 1.02 MeV.

The threshold frequency is the correct term for the minimum frequency needed to overcome the work function of the metal and eject an electron.

The de Broglie equation correctly relates a particle's wavelength (λ) to its momentum (p) via Planck's constant (h).

The principle's most common formulation states a fundamental limit to the precision with which the position and momentum of a particle can be known simultaneously (ΔxΔp ≥ h/4π).

According to Einstein's photoelectric equation (K.E. = hf - φ), the maximum kinetic energy of photoelectrons is determined by the frequency of the incident light, not its intensity.

The work function is a property of a given metal that defines the minimum energy (binding energy) needed for an electron to escape from its surface.

De Broglie extended wave-particle duality to all matter, proposing that any moving particle with momentum 'p' has an associated wavelength given by λ = h/p.

The photoelectric effect is correctly defined as the emission of electrons (photoelectrons) from a material upon exposure to electromagnetic radiation of a suitable frequency.

The Compton effect, where an X-ray photon scatters off an electron and loses energy, is explained by treating the photon as a particle with momentum (p = h/λ), conserving both energy and momentum in the collision.

Photocells operate based on the photoelectric effect, generating a current when exposed to light, thus converting light energy into electrical energy.

Pair production is the conversion of energy (a high-energy photon) into matter, creating a particle-antiparticle pair (electron and positron) to conserve charge and other quantum numbers.

The relationship is inverse; according to the uncertainty principle, if you know the position more precisely (smaller Δx), you must know the momentum less precisely (larger Δp).