How to draw Ray Diagrams

• What type of lenses cause light rays to diverge?

  Concave lenses
• What symbol is used to represent a concave lens in ray diagrams?

  A lens with outward pointing V shapes
• What is the horizontal line through the middle of the lens called?

  Axis
• What are the focal points in relation to a lens?

  Points where light rays converge or diverge
• What is another term for the focal point?

  Principal focus
• What does the label '2f' represent in ray diagrams?

  Twice the distance of the focal point
• If an object is represented by a chicken, what is the first step in drawing a ray diagram?

  Pick a point near the top of the object
• What happens to the ray that goes through the center of the lens?

  It continues straight without refraction
• How do you find the angle at which a ray is refracted?

  Draw a virtual ray to the focal point
• What do you do after drawing all the light rays in a ray diagram?

  Find the point where they cross
• What can be said about the image formed by a concave lens?

  It is always virtual and upright
• What type of lenses focus light onto a single point?

  Convex lenses
• How are convex lenses represented in ray diagrams?

  With V shapes that get narrower towards the ends
• What happens to the ray that passes through the middle of a convex lens?

  It continues straight without refraction
• How do you determine the location of the image in a convex lens ray diagram?

  Find the spot where the rays cross
• What characteristics describe the image formed by a convex lens when the object is more than two focal lengths away?

  It is real, inverted, and smaller
• What happens if the object is exactly at two focal lengths from a convex lens?

  The image is real and the same size
• What occurs if the object is between the focal point and the lens?

  The rays do not meet, forming a virtual image
• What are the key differences between concave and convex lenses in ray diagrams?

  • Concave lenses cause light to diverge
  • Convex lenses focus light to a point
  • Concave lenses always produce virtual images
  • Convex lenses can produce real or virtual images
• What are the steps to draw a ray diagram for a concave lens?

  1. Draw the concave lens symbol
  2. Add the axis and focal points
  3. Draw incident rays from the object
  4. Identify the point where rays cross
  5. Comment on the image characteristics
• What are the steps to draw a ray diagram for a convex lens?

  1. Draw the convex lens symbol
  2. Add the axis and focal points
  3. Draw incident rays from the object
  4. Identify the point where rays cross
  5. Comment on the image characteristics
• What are the characteristics of images formed by lenses?

  • Concave lens: virtual, upright, smaller
  • Convex lens (beyond 2f): real, inverted, smaller
  • Convex lens (at 2f): real, inverted, same size
  • Convex lens (between f and 2f): real, inverted, larger
  • Convex lens (between f and lens): virtual, upright, larger