Convex lenses and where images form

Answer Key - Grade 11 Science Worksheet - Challenge Me

Circle the best answer, or write your answer on the line.

1. 1.

   Use the sign rule on the sheet. A magnifying glass has f = 20 cm, and a stamp sits 12 cm from it. What is di, Bo?

   -30 cm
2. 2.

   Use the sign rule on the sheet. A magnifying glass has f = 12 cm, and a stamp sits 8 cm from it. What is di, Esme?

   -24 cm
3. 3.

   An object 30 cm from a lens gives a sharp image 15 cm on the other side. What is the focal length, Jun?

   • 45 cm
   • 10 cm
   • 22.5 cm
4. 4.

   A lens makes a same-size real image when the object and image are each 40 cm away. What is f, Kira?

   • 40 cm
   • 20 cm
   • 80 cm
5. 5.

   An object 12 cm from a lens gives a sharp image 60 cm away. What is the focal length, Luz?

   • 10 cm
   • 72 cm
   • 48 cm
6. 6.

   Milo says a real image made by one convex lens is upright. Agree or disagree?

   • Agree: lenses keep things the right way up
   • Agree: real images match the object
   • Disagree: it is upside down
7. 7.

   Noah says the image on a camera's sensor is the right way up. Agree or disagree?

   • Agree: real images are upright on the sensor
   • Disagree: it is inverted on the sensor
   • Agree: the image is virtual
8. 8.

   To use a lens as a magnifier, where must the object be placed, Ren?

   • Exactly at twice the focal length
   • Far beyond the focal point
   • Closer to the lens than its focal length
9. 9.

   A projector's image is too small on the screen. How should the slide be moved, Tala?

   • Closer to the focal point, with the screen moved back
   • Farther from the lens
   • Inside the focal length
10. 10.

    A camera focuses on mountains far away. About where must its sensor sit, Zee?

    • At twice the focal length
    • At about one focal length behind the lens
    • Right against the lens