Physics prelim

• What do all waves transfer?

  Energy from one place to another
• What is the unit of frequency?

  Hertz (Hz)
• What is wavelength represented by?

  λ (lambda)
• What is the peak of a wave called?

  Peak
• What is the bottom of a wave called?

  Trough
• How do particles behave in a transverse wave?

  They vibrate at 90° to wave direction
• What type of waves are all electromagnetic (EM) waves?

  Transverse waves
• How do particles behave in a longitudinal wave?

  They vibrate parallel to each other
• What is the formula to find the speed of a wave?

  V = fλ or d = vt
• What does frequency measure?

  Number of waves per time
• What is the period of a wave?

  Time for one wave to pass a point
• What is the speed of all EM waves?

  3x10⁸ m/s
• How does frequency change across the EM spectrum?

  It decreases from gamma rays to radio waves
• What are the types of electromagnetic waves in order of increasing wavelength?

  • Gamma Rays
  • X-Rays
  • UV
  • Visible Light
  • Infrared
  • Micro Waves
  • Radio Waves
• What are some sources of radio waves?

  Mobile phones, stars, and the sun
• What is diffraction?

  When a wave bends around an object
• How does the size of a gap affect diffraction?

  Large gap = less diffraction; small gap = more diffraction
• What happens to waves when they travel from one medium to another?

  They change speed, called refraction
• What is the point where a wave enters a new medium called?

  The normal
• What happens to a wave in a more dense medium?

  It bends towards the normal and slows down
• What happens to a wave in a less dense medium?

  It bends away from the normal and speeds up
• What is total internal reflection?

  When a wave reflects entirely within a medium
• What is the charge of an electron?

  • 1
• What is the charge of a proton?

  +1
• What is an isotope?

  Same element with different neutrons
• What is the nucleus composed of?

  Protons and neutrons
• How do you calculate the number of nucleons in an atom?

  Number of protons + neutrons
• What are alpha particles composed of?

  2 protons and 2 neutrons
• What is the charge of alpha particles?

  They have a charge of +2
• What are beta particles?

  Fast-moving electrons
• What is the charge of beta particles?

  They have a charge of -1
• What are gamma rays?

  Electromagnetic waves with no charge
• What is radioactive decay?

  A random process of unstable nuclei breaking down
• What can stop alpha particles?

  Paper or skin
• What can stop beta particles?

  Aluminum
• What can stop gamma rays?

  Lead or concrete
• What is activity in radioactive decay?

  Number of decays per unit time
• What is half-life?

  Time for activity to fall to half
• What equipment is used to find half-life in an experiment?

  • A Geiger-Muller tube (GM)
  • A stop clock
  • A radioactive source
• How do you measure count rate in a half-life experiment?

  Count in a set time period