10 minutes maximum! Can you do it in 5?

1. The diagrams show two lenses labelled X and Y. What are the names of these types of lenses?

two types of lenses X and Y
X Y
A
 converging converse
B
 diverging converging
C
 converging diverging
D
 converse diverging

2. Which of these is the symbol for a diverging lens?

diverging lens symbol, 4 choices

3-5. These questions are about the diagram shown here, with parallel rays of light passing through a lens.

ray diagram with converging rays

3. What is the name given to the point X and the length shown as Y?

 Point X length Y
A
 virtual point axis length
B
 principal focus focal length
C
 focal axis axis length
D
 point of convergence focal length

 

4. Light rays that are near parallel before entering the lens must be coming from..

  • A. a distant object
  • B. a near by object
  • C. a virtual image
  • D. a real image

5. The rays of light can be bought to a focus on a screen. This means the image must be..

  • A. virtual
  • B. real
  • C. imaginary
  • D. magnified

6-8. The diagram here shows one ray of light coming from an object and entering a lens. The focal point F is labelled.

ray diagram for converging lens, partially complete

By sketching and completing this ray diagram to show the formation of an image, answer the following questions:

6. A light ray passing from the top of the object through the centre of the lens will...

  • A. pass through point F
  • B. be refracted upwards on the diagram
  • C. be refracted downwards on the diagram
  • D. continue in a straight line

7. What type of image is formed?

  • A. real and inverted
  • B. real and the right way up
  • C. virtual and inverted
  • D. virtual and the right way up

8. How does the size of the image compare to the original object?

  • A. magnified
  • B. diminished
  • C. same size
  • D. none of the above as image is virtual

9. Virtual images are created when the lens makes light rays diverge. The brain expects the rays to have travelled in a straight line and come from the same side of the lens as the object.

Which of the following arrangements can create a virtual image?

I. A converging lens, with the object further away from the lens than the focal length
II. A converging lens, with the object closer to the lens than the focal length
III. All diverging lenses, irrespective of the object placement
  • A. I and III
  • B. II and III
  • C. II only
  • D. III only

10. Which of the following statements is ALWAYS true for virtual images, regardless of the lens used or placement of the object?

  • A. always magnified
  • B. always inverted
  • C. always the right way up
  • D. always diminished