15.1 Quantum Physics

• Quantum physics studies the behavior of matter and energy on the atomic and subatomic scale
• Planck discovered that energy is emitted or absorbed in discrete packets called quanta
• Planck's quantum theory states that the energy of an oscillating atom or molecule is restricted to certain discrete
• Planck's quantization discovery showed that energy is emitted or absorbed in indivisible packets called quanta.


  True
• What is the formula for the kinetic energy of emitted electrons in the photoelectric effect?

  KE = hf - \Phi</latex>
• What is the key difference between classical and quantum physics views on light scattering?

  Wavelength shift in quantum physics
• Arrange the historical milestones in the development of quantum physics:

  1️⃣ Max Planck proposes quantization of energy

  2️⃣ Einstein explains the photoelectric effect

  3️⃣ Compton effect provides evidence for particle nature of light
• In 1900, Max Planck proposed the revolutionary idea of quantization to explain energy changes, which occur in discrete packets called quanta
• Who proposed the concept of quantization in 1900?

  Max Planck
• Order the following key concepts of Planck's quantum theory:

  1️⃣ Energy is not continuous

  2️⃣ Energy is emitted in quanta

  3️⃣ Energy values are discrete

  4️⃣ Explained blackbody radiation
• What phenomenon could Planck's quantum theory explain that classical physics could not?

  Blackbody radiation
• The minimum energy required for an electron to escape a metal surface is called the work function.
• In the Compton effect, the change in wavelength is called the Compton shift.
• Planck's quantum theory introduced the concept of energy quantization.
• Match the concepts with their related fields:

  Continuous energy changes ↔️ Classical physics

  Discrete energy values ↔️ Quantum physics
• Match the concept with its description in classical versus quantum physics:

  Energy changes ↔️ Classical: Continuous, Quantum: Discrete

  Energy description ↔️ Classical: Continuous variable, Quantum: Indivisible quanta

  Explaining blackbody radiation ↔️ Classical: Unable, Quantum: Planck's theory
• In the photoelectric effect, the minimum energy required for an electron to escape a metal surface is called the work function
• Classical physics can adequately explain phenomena at the quantum level.

  False
• Planck's quantum theory states that the energy of an oscillating atom can take on any arbitrary value.

  False
• Classical physics assumes continuous energy changes, while quantum physics assumes discrete energy changes.


  True
• Steps in Einstein's quantum explanation of the photoelectric effect:

  1️⃣ Light consists of photons with energy E = hf

  2️⃣ Electrons need a minimum energy (work function) to escape

  3️⃣ Electrons are emitted if hf > Φ

  4️⃣ Kinetic energy of emitted electrons is KE = hf - Φ
• Match the scattering effect with its corresponding description:

  Compton effect ↔️ Scattering of photons by charged particles with a wavelength shift

  Rayleigh scattering ↔️ Scattering by particles smaller than the wavelength

  Mie scattering ↔️ Scattering by particles equal to or larger than the wavelength
• Quantum physics describes the world in terms of probabilities, while classical physics describes it in terms of certainties.

  True
• What are the indivisible packets of energy discovered by Planck called?

  Quanta
• What does Planck's quantum theory state about the energy of an oscillating atom or molecule?

  Discrete values only
• What is the formula for the energy of a photon in Einstein's quantum explanation of the photoelectric effect?

  $E =$$hf$
• Einstein's quantum model of the photoelectric effect successfully explains the dependence on light frequency.


  True
• In the Compton effect formula, \(h\) represents Planck's constant
• What happens to the photon's energy in the Compton effect?

  It decreases
• Match the light scattering effect with its key characteristic:

  Compton effect ↔️ Photon's wavelength shifts

  Rayleigh scattering ↔️ No wavelength shift

  Mie scattering ↔️ Scattering by larger particles
• In classical physics, light scattering results in a change in wavelength.

  False
• The Compton shift occurs because a photon loses energy during scattering.

  True
• What is De Broglie's hypothesis?

  All matter exhibits wave-like behavior
• Match the variables in the De Broglie wavelength formula with their meanings:

  h ↔️ Planck's constant

  p ↔️ Momentum of particle

  m ↔️ Mass of particle

  v ↔️ Velocity of particle
• What is the uncertainty principle formula for position and momentum?

  \Delta x \cdot \Delta p \geq \frac{h}{4\pi}</latex>
• Unlike classical physics, quantum physics follows probabilistic laws of quantum mechanics.
• Quantum physics deals with large-scale objects.

  False
• Quantum physics describes the world in terms of certainties.

  False
• Planck's theory states that the energy of an atom can take on any arbitrary value.

  False
• What did Planck discover about energy emission and absorption?

  It occurs in discrete packets