topic 5

• reflection

  The bouncing of a wave when it hits a surface
• angle of incedence


  the angle formed by the wave striking the surface and the normal
• angle of reflection


  The angle between the reflected ray and the normal
• concave lens


  a lens that is thicker at the edges than in the middle that bends light rays away from the center
• convex lens


  A lens that is thicker in the middle than at the edges and bends light rays towards the center
• The focal point of a lens is


  the point where all incident parallel rays meet after being refracted
• real image


  formed when light rays converge to form the image
• virtual image


  an image that forms at a location where light rays appear to come from but do not actually come
• Frequency


  The number of complete waves that pass a given point in a certain amount of time
• Amplitude


  Height of a wave
• Refraction


  The bending of a wave as it passes at an angle from one medium to another
• radio waves


  Electromagnetic waves with the longest wavelengths and lowest frequencies
• speed of light


  300,000 km/s
• speed of sound


  340 m/s
• microwaves


  used for cooking and wireless communication
• infrared


  invisible short frequencies of light before red in the visible spectrum
• visible spectrum


  Light energy that can be seen and can be broken into the colors of the rainbow.
• ultra violet (uv) light


  shorter-wavelength, higher-energy rays from the Sun that can damage living tissue
• X-rays


  Electromagnetic waves with wavelengths just shorter than those of ultraviolet rays, can be used to form images of bones and internal organs
• gamma rays


  highest-energy electromagnetic waves with the shortest wavelengths and highest frequencies, given off during nuclear reactions
• ROYGBIV


  Colors of the visible spectrum in order of longest to shortest wavelength
• retina


  layer at the back of the eye that receives images

  
• pupil


  opening in the center of the iris in the eye
• rod cells


  work best in dim light and enable you to see black, white, and shades of gray

  
• cone cells


  operate best in bright light; enable high-acuity, color vision

  
• difraction


  the spreading out of waves as they pass through an opening or around the edges of an obstacle

  
• transparent


  Allowing light to pass through

  
• translucent


  Allowing light to pass through, but scattered

  
• opaque


  not letting light through