13.4 Lenses and Image Formation

• Concave lenses are thicker in the middle and narrower at the edges.

  False
• What type of image is formed by a concave lens?

  Virtual, upright, smaller
• Concave lenses diverge light rays to form a virtual image.
• What is the focal length of a convex lens considered?

  Positive
• The focal point is where parallel light rays converge after passing through a convex lens.
• In sign conventions, a positive object distance indicates the object is on the same side of the lens as the incoming light.
• What is the focal length of a concave lens according to sign conventions?

  Negative
• A convex lens can form both real and virtual images.


  True
• In the thin lens equation, the focal length is positive for a convex lens.
• What is the focal length of a lens in the thin lens equation?

  f
• The focal length of a concave lens is positive.

  False
• A concave lens is thinner in the middle
• Convex lenses diverge light rays.

  False
• What is the shape of a convex lens?

  Thicker in the middle
• The focal length of a convex lens is negative.

  False
• Match the lens type with its focal length sign:

  Concave Lens ↔️ Negative

  Convex Lens ↔️ Positive
• What is the sign of the focal length for a convex lens?

  Positive
• The magnification of a convex lens is negative if the image is inverted
• What is crucial for analyzing the properties of images formed by lenses?

  Drawing ray diagrams
• For concave lenses, the focal length is negative
• What type of magnification does a concave lens produce?

  Negative
• Arrange the following components of the thin lens equation in their correct order:

  1️⃣ 1/f

  2️⃣ =

  3️⃣ 1/d_o

  4️⃣ +

  5️⃣ 1/d_i
• What does d_o represent in the thin lens equation?

  Object distance
• The magnification formula includes the ratio of image height to object height.


  True
• Real images are formed on the opposite side of the lens from the object.
• In ray tracing, the parallel ray refracts through the focal point.


  True
• If the rays converge in ray tracing, the image is real.
• Arrange the three principal rays in the order of their description during ray tracing:

  1️⃣ Parallel ray

  2️⃣ Focal ray

  3️⃣ Central ray
• Ray tracing techniques can be used to determine the location and magnification of an image formed by a lens.


  True
• The key to effective ray tracing is identifying and drawing the principal rays
• A parallel ray is a ray parallel to the principal axis that refracts through the focal point.


  True
• A ray passing through the center of the lens continues unrefracted
• A focal ray is a ray passing through the focal point that refracts parallel to the principal axis.


  True
• The parallel ray in a concave lens diverges after passing through the lens
• What happens to a parallel ray in a concave lens after passing through it?

  It diverges
• The central ray in a concave lens continues unrefracted.


  True
• What happens to a focal ray in a convex lens after passing through it?

  It refracts parallel to the principal axis
• Convex lenses can form real or virtual images that can be inverted or upright, and larger or smaller than the object.


  True
• What are the two main types of lenses?

  Concave and convex
• Convex lenses converge light rays.