5.2 Lenses

• Concave lenses diverge light away from a focal point.


  True
• The shape of a lens determines how it refracts light
• Order the image characteristics based on object distance for a convex lens:

  1️⃣ Beyond 2f: Real, Inverted, Reduced

  2️⃣ At 2f: Real, Inverted, Same Size

  3️⃣ Between f and 2f: Real, Inverted, Magnified

  4️⃣ At f: No Image Formed

  5️⃣ Less than f: Virtual, Upright, Magnified
• A longer focal length in a convex lens results in a smaller image
• What does the lens equation relate?

  Object distance, focal length, image distance
• Convex lenses are also known as diverging lenses.

  False
• A longer focal length in a convex lens corresponds to more curvature
• What are the characteristics of the image formed when u > 2f with a convex lens?

  Real, inverted, reduced
• What type of image is formed when u < f with a convex lens?

  Virtual, upright, magnified
• Match the lens type with its image characteristics:

  Convex lens ↔️ Image varies based on object distance

  Concave lens ↔️ Virtual, upright, reduced image
• Concave lenses diverge light away from a focal point
• Magnification is the ratio of image size to object size
• Convex lenses are thick in the center
• What is the primary function of a convex lens?

  Converge light
• Match the lens type with its focal length property:

  Convex ↔️ Longer focal length

  Concave ↔️ Shorter focal length
• As the object distance increases, the image distance decreases, and the image size becomes smaller.


  True
• A shorter focal length in a concave lens means less curvature
• Convex lenses have a longer focal length, more curved surface, and stronger magnification
• What type of magnification do concave lenses produce?

  Weaker
• The lens equation relates object distance, focal length, and image distance.

  True
• When u < f with a convex lens, the rays converge on the opposite side to form a real image.

  False
• The lens formula relates object distance, image distance, and focal length.


  True
• If an object is placed 30 cm from a convex lens with a focal length of 10 cm, the magnification is 0.5.


  True
• What are the two main types of lenses?

  Convex and concave
• Match the lens type with its characteristic:

  Convex ↔️ Thick in the center

  Concave ↔️ Thin in the center
• The focal length of a lens is the distance to its focal point.


  True
• What is the formula for magnification with lenses?

  \text{Magnification} = \frac{\text{Image Distance}}{\text{Object Distance}}\end{latex>
• What type of magnification does a convex lens with a longer focal length produce?

  Stronger
• What is the focal length of a lens defined as?

  Distance to the focal point
• When u = 2f with a convex lens, the image formed is real, inverted, and of the same size
• Steps in visualizing image formation using a ray diagram with a convex lens

  1️⃣ Ray from object parallel to principal axis refracts through focal point

  2️⃣ Ray through lens center goes straight

  3️⃣ Ray through focal point on same side refracts parallel to principal axis

  4️⃣ Intersection of rays forms the image
• What is a primary application of concave lenses?

  Corrective eyeglasses
• What is the image size formed by a concave lens compared to the object?

  Smaller
• What does a negative magnification indicate about the image?

  Virtual, upright