ray diagram revision

We’ve reached the Space unit and are almost at the end of the course.  I showed you how to draw ray diagrams when we looked at lenses during the Health Physics unit.  Some people have asked me to repost these video clips as they were not sure how to draw ray diagrams for our telescope this morning.

Watch these clips and make sure you know the six terms we use to describe the image formed by a lens. You should be able to select three words to describe the image in your ray diagram.

how to draw a ray diagram from mr mackenzie on Vimeo.

The second video looks at a ray diagram when the object is less than one focal length away from the lens.

ray diagram for objects closer than 1f from mr mackenzie on Vimeo.

Once the ray diagram is complete, we need to describe the image that has been formed.  The description must tell us about the size, orientation and type of image that is formed.

Size
If the image is larger then the original object, we say the image is magnified
If the image is smaller than the original object, we say the image is diminished.

Orientation
If the image is the same way up as the object, we describe it is upright.
If the image is upside down compared to the object, we describe it as inverted.

Type
If the object and image are on opposite sides of the lens, it is a real image.
If the object and image are on the same side of the lens, it is a virtual image.

2 thoughts on “ray diagram revision

    • I’m not in the business of predicting what will or will not come up in the exam. The 2009 credit paper had a ray diagram in Q16. The good news is that you write your answers on the Standard Grade papers, so part of the ray drawing will probably be on the page already – all you have to do is complete the picture.

Leave a Comment