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