Physics quiz

• Mirrors

  Optical devices that permit the reflection of light
• Two types of Mirrors

  • Planar or spherical
• Plane mirrors


  Will always form an image that has the same size as the object, the light rays incident to it simply bounce back and do not change their direction with respect to how they approach the mirror, the image form is erect or upright
• The focal point of a plane mirror does not exist in its real side (same side as the object), it must be in the virtual side that renders the formed image as virtual
• When you look directly into a plane mirror, you will see the reflected images of yourself and the objects around you. If you turned the light off in a bathroom to make the room completely dark, the image will disappear. The image will only appear when the light is turned back on
• Plane mirrors


  • Produce images that appear to be as far behind the mirror as the image is in front, the only defect is the reversal effect, the right side of the object appears as the left side appears as the right - the image is flipped from left to right
• The letters from the word AMBULANCE were printed backwards and are reversed in sequence so that they appear in the proper orientation and order when seen in a rearview mirror
• Size and position of the image formed in a plane mirror


  Image is virtual, erect, same size as object and laterally inverted, image distance equals object distance
• Curved mirrors


  Commonly spherical mirrors, the reflecting surface is part of a large sphere, have a vertex, center of curvature, and principal focus
• Concave mirror


  • Also known as converging mirror, with a surface that curved inward like the inside of a bowl, turns parallel rays into convergent rays
• Uses of concave mirrors


  • Magnifying mirrors for shaving and applying makeup
  • Reflecting telescopes
  • Making the beam of light in flashlights and car headlights
• Convex mirror


  Also known as diverging mirror, with a surface that curves outward, can reflect parallel rays of light so that they apparently meet at a point behind the mirror

  
• Summary of how different mirrors form images


  • Plane mirror: Same size, erect, virtual
  • Concave mirror: Enlarged, inverted, real
  • Convex mirror: Diminished, erect, virtual

  
• Power of a mirror


  Inverse of the focal length
• Radius of curvature


  Twice the focal length
• Magnification of a mirror


  Ratio of image height to object height, or ratio of image distance to object distance
• Sign convention for image formation by mirrors

  • Plane mirror: +, no real image, -, N/A, +, not inverted
  • Convex mirror: -, no real image, -, +, +, -
  • Concave mirror: -, +, -, -, +, +
• Sign convention for image formation by lenses


  • Concave or converging lens: -, +, -, -, +, +, -
  • Convex or diverging lens: -, +, -, +, +, +, -

  
• Thin lens equation


  1/f = 1/d0 + 1/di, where f is focal length, d0 is object distance, and di is image distance

  
• Example 1: Concave mirror


  • Given: h0 = 5 cm, d0 = 50 cm, f = 15 cm. Calculated: di = -21.43 cm, hi = 2.143 cm

  
• Example 2: Diverging lens


  • Given: h0 = 10 cm, d0 = 30 cm, f = -15 cm. Calculated: di = -10 cm, hi = 3.33 cm
• Example 3: Convex mirror


  • Given: h0 = 5 cm, d0 = 10 cm, f = 15 cm. Calculated: di = -30 cm, hi = 15 cm
• Example 4: Converging lens


  • Given: h0 = 0.10 m, d0 = 0.75 m, f = 0.25 m. Calculated: di = 0.375 m, hi = -0.05 m
• Mirrors reflect what the object looks like. In life, how do you reflect or show the positive values of your family to the people you deal with everyday?
• Lenses


  Clear optical media that allow the penetration of light rays through them, and then bend them
• Converging lens


  • Thicker at the center than at the rim and will "converge" or focus its refracted rays to a single point
• Diverging lens


  • Thinner at the center than at the rim and will "diverge" or scatter its refracted rays from a virtual point
• Summary of how lenses form images

  • Converging lens: Outside focal point - smaller, inverted, real; Between focal point and lens - enlarged, erect, virtual
  • Diverging lens: Smaller, erect, virtual
• Converging lenses concentrate refracted rays to a single point, used to create images for the eyes of individuals suffering from farsightedness. Diverging lenses scatter these rays, a pair is needed to correct the vision of those suffering from nearsightedness
• Energy can be transferred from one object to another by work done, heat transfer, or radiation.
• The SI unit of energy is the joule (J).
• Work done is calculated as force times distance moved in the direction of the force.
• Work done is defined as force multiplied by distance moved in the direction of the force.