Physics Review Question

Unit: optics
Year: 1995 Question#: 89
Question: Which piece of glass could be used to focus parallel rays of sunlight to a small spot of light?

(1 )

(2 )

(3 )

(4 )

What is this question really asking?

Explanation by: Andy D.
[ Return to question menu ]

Answer 1


This is incorrect, because the lines of light would not converge or diverge - they would continue without changing angle. ex: 
return to top

Answer 2


This is the correct answer, because the light DOES converge at a point! Presto! If you guessed this, you are correct. The light is bent towards a focal point, where it converges.  return to top

Answer 3


This lens would make the light diverge, and so the light would not collect into one little packet. In fact, it would do quite the opposite.  return to top

Answer 4


This is a prism. It does not collect light. It breaks it up into component colors. It does not meet the criterium for this question.

return to top

What's this question really asking?

This question is asking which one of the lenses bends light towards one focal point. return to top

[Physics Lessons]  [Physics Review]  [Physics Links]

This web site is designed and maintained by Science Joy Wagon and may not be reproduced or redistributed without written permission from Science Joy Wagon.
Contact with comments.