paper 2

• What are longitudinal waves?

  Waves where oscillations are parallel to energy transfer
• What are compressions and rarefactions in longitudinal waves?

  Compressions are where particles bunch up; rarefactions are spread out
• What are transverse waves?

  Waves where oscillations are perpendicular to energy transfer
• What is the amplitude of a wave?

  Maximum displacement from equilibrium
• What does the symbol Lambda (λ) represent?

  Wavelength of a wave
• What is the time period of a wave?

  Time taken for one complete wave to pass
• How are frequency and time period related?

  They are reciprocals of each other
• How do you calculate frequency from a waveform?

  Measure time period and do 1 divided by that
• What is the wave equation?

  V = F × λ
• How can you measure the speed of a wave in a ripple tank?

  Measure distance between 10 peaks and divide by 10
• How can you measure the speed of sound waves?

  Use a microphone and oscilloscope to measure time
• What frequency range can the human ear hear?

  20 Hz to 20 kHz
• What happens when sound reaches a boundary between two different mediums?

  Some sound is transmitted, some is reflected
• How does ultrasound work in medical imaging?

  It builds an image by timing echoes from layers
• What is sonar used for?

  To build a picture of underwater objects
• Why can't transverse S waves travel through liquids?

  Because they require a medium to propagate
• What does the absence of aftershocks on the opposite side of the Earth imply?

  That the Earth has a molten core
• What is specular reflection?

  Reflection off a smooth surface without scattering
• What is the angle of incidence?

  Angle measured from the normal to the incoming ray
• What happens to light waves when they move from air to glass?

  They change speed and wavelength decreases
• What is refraction?

  Change in direction of waves when entering a new medium
• How does the angle of refraction compare to the angle of incidence?

  Angle of refraction is smaller if light slows down
• What is a convex lens?

  A lens that converges rays of light
• What is the principal focus of a convex lens?

  Point where parallel rays converge
• What is the focal length of a lens?

  Distance from the center of the lens to the focus
• How do convex lenses project images?

  By converging light rays from the object
• What happens when an object is very close to a convex lens?

  Image is virtual, upright, and magnified
• What is a concave lens?

  A lens that diverges rays of light
• What is the magnification of a lens?

  Ratio of image height to object height
• What determines the color we perceive?

  Different wavelengths of light emitted or reflected
• What is a black body in physics?

  An object that perfectly absorbs and emits radiation
• What happens if an object absorbs radiation faster than it emits?

  Its temperature will increase
• What is radiation in physics?

  Any particle or wave emitted by something
• What types of radiation can nuclei emit?

  Alpha, beta, and gamma radiation
• What is alpha decay?

  Emission of two protons and two neutrons
• What is the atomic number of an alpha particle?

  2
• What happens to the atomic number during alpha decay?

  It decreases by 2
• What is beta decay?

  A neutron turns into a proton and an electron
• What is the charge of a beta particle?

  Negative charge
• What is the ionizing ability of alpha particles?

  High ionizing ability