Physics: Planck's Constant Quiz

Chapter 11: Modern Atomic Theory

• This chapter covers modern atomic theory, including Rutherford's gold foil experiment, the nuclear model, electromagnetic radiation, and the dual nature of light.

Rutherford's Gold Foil Experiment

• Observations: Most alpha particles passed straight through the gold foil, some were deflected at small angles, and a few were deflected back.
• Interpretations: The atom is mostly empty space. A small, dense, positively charged nucleus is at the center, which deflects alpha particles. The nucleus holds most of the atom's mass.

Rutherford's Atom

• Nuclear Model: The atom has a small, dense, positively charged nucleus containing protons. Neutrons, with no charge, are also in the nucleus. The remainder of the atom consists of mostly empty space and electrons with a negative charge.
• Electron Arrangement/Movement: The text discusses electrons moving around the nucleus. Questions about the specific arrangement and movement are raised.

Electromagnetic Radiation

• Definition: A type of energy that travels through space as waves.
• Characteristics:
  • Wavelength (λ): The distance between two peaks or troughs in a wave. Measured in meters (m).
  • Frequency (ν): The number of waves that pass a given point in space per second. Measured in Hertz (Hz).
  • Speed of light (c): The speed at which electromagnetic waves travel. Approximately 2.9979 × 10⁸ m/s.
• Relationship between wavelength and frequency: c = λν
• Energy and Frequency: Energy (E) of a photon is equal to Planck's constant (h) multiplied by the frequency (ν). E = hν
• Energy and Wavelength: Energy (E) is also related to the wavelength (λ) E=hc/λ where h is Planck's constant (6.626 x 10⁻³⁴ J⋅s) and c is the speed of light
• Types of Electromagnetic Radiation:
  • The electromagnetic spectrum includes gamma rays, X-rays, ultraviolet light, visible light, infrared radiation, microwaves, and radio waves. Different wavelengths carry different amounts of energy. Visible light is in the middle of this spectrum.

Dual Nature of Light

• Light exhibits properties of both waves and particles.
• Particles of light are called photons.
• Energy of a photon (E) is equal to Planck's constant (h) times the frequency (ν) E = hν
• The energy of a photon is also related to wavelength by E=hc/λ, where c is the speed of light.

De Broglie Wavelength

• λ = h / mv
• λ = wavelength in meters
• v = velocity in meters/second
• m = mass in kilograms
• h = Planck's constant