PHY1071 Engineering Physics Common Course Material

What does the de Broglie hypothesis propose about matter?

It proposes that all forms of matter have wave-like properties, similar to light.

What is the formula for de Broglie wavelength?

λ = h / p, where h is Planck's constant and p is the momentum of the particle.

What are the two primary characteristics of light according to its dual nature?

Light exhibits both wave properties (like diffraction and interference) and particle properties (like photoelectric and Compton effects).

What was the key conclusion of the Davisson-Germer experiment?

It provided experimental evidence for the wave nature of electrons, supporting the de Broglie hypothesis.

What equation relates the kinetic energy of an electron accelerated through a potential difference?

The kinetic energy is given by KE = eΔV, where e is the charge of the electron and ΔV is the potential difference.

What does Heisenberg's uncertainty principle state?

It is impossible to simultaneously know the exact position and momentum of a particle.

Describe the relationship between group speed and phase speed in wave packets.

Group speed (vg) is the speed at which the envelope of the wave packet travels, while phase speed (vp) is the speed of the individual wave crests.

What phenomenon provides evidence for the wave nature of light?

Diffraction and interference patterns observed in experiments.

State the equation that demonstrates the relationship between wavelength and diffraction in the context of double-slit experiments.

d sin(θ) = mλ, where d is the slit separation, θ is the angle of the maximum, and m is the order number.

What is the significance of the wave packet in quantum mechanics?

A wave packet represents a localized quantum particle, formed by superimposing many waves.

How does the Compton effect illustrate the particle nature of light?

It shows that light behaves as particles (photons) when scattering off electrons, resulting in a shift in wavelength.

What is the relationship between frequency (f) and energy (E) of a photon?

E = hf, where h is Planck's constant.

What is described by the principle of complementarity in quantum mechanics?

It states that wave and particle models of matter or radiation are complementary, both necessary to fully describe phenomena.

What happens to the wavelength of scattered X-rays when the detection angle increases in the Compton effect?

The wavelength of the scattered X-rays increases as the angle increases.

What is the formula for the momentum (p) of an electron with mass m and velocity v?

p = mv, where m is the mass of the electron and v is its velocity.

In the context of the photoelectric effect, what is the work function?

The minimum energy required to eject an electron from a metal surface.

What does the photoelectric effect confirm about light?

It confirms the particle nature of light, as light can cause the emission of electrons from metals.

Explain the significance of Planck's constant (h) in quantum physics.

Planck's constant relates the energy of a photon to its frequency, establishing the quantization of energy.

What is the uncertainty relation involving position (Δx) and momentum (Δp)?

Δx * Δp ≥ h / 4π, indicating that precise measurements of one variable lead to uncertainty in the other.

What is the maximum kinetic energy of photoelectrons in the photoelectric effect?

The maximum kinetic energy is given by KE = hf - φ, where φ is the work function.