Convex lenses and where images form

Answer Key - Grade 11 Science Worksheet

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

1. 1.

   Use the sign rule on the sheet. A convex lens has f = 10 cm, and an object sits 30 cm from it. What is the image distance, Ari?

   15 cm
2. 2.

   Use the sign rule on the sheet. A convex lens has f = 20 cm, and an object sits 60 cm from it. What is the image distance, Bo?

   30 cm
3. 3.

   Use the sign rule on the sheet. A convex lens has f = 15 cm, and an object sits 25 cm from it. What is the image distance, Esme?

   37.5 cm
5. 4.

   Using the table, at what object distance is the image the same size as the object, Jun?

   • 30 cm
   • 20 cm
   • 10 cm
6. 5.

   Using the table, which object distance gives a virtual image, Kira?

   Use the picture in question 4.

   • 5 cm
   • 30 cm
   • 15 cm
7. 6.

   Using the table, as the object moves from 30 cm to 15 cm, what happens to the real image, Luz?

   Use the picture in question 4.

   • It moves closer and gets smaller
   • It stays in the same place
   • It moves farther away and gets bigger
8. 7.

   Use the sign rule on the sheet. A thin-lens answer comes out as di = −12 cm. What does the minus sign mean, Milo?

   • Nothing: distances can't be negative
   • The image is virtual, on the object's side
   • The image is real and twice as far
9. 8.

   An object is 30 cm from a convex lens and its image is at di = 15 cm. Using m = −di ÷ do, what is the image like, Ren?

   • Half size and upside down
   • Twice the size and upright
   • Half size and upright
10. 9.

    An object is 5 cm from a convex lens and its image is at di = −10 cm. Using m = −di ÷ do, what is the image like, Tala?

    • Twice the size and upright
    • Half the size and upright
    • Twice the size and upside down
11. 10.

    A 2 cm object is 15 cm from a convex lens, and its image is at di = 30 cm. How tall is the image, Zee?

    • 4 cm, upside down
    • 1 cm, upside down
    • 4 cm, upright