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Refracting Light with a Lens

A lens forms an image by refracting light. Depending on the lens, this image can be enlarged or diminished, upright or inverted.

In this lesson we will look at how we can use refraction in lenses to create images. For example, what do we use a magnifying glass for?

Out of these options, which do you think use lenses in order to create images? Pick all the options you think are correct.

You can select multiple answers

Lets recall what the definition of refraction is ...

So refraction bends light. Lenses use refraction to focus rays of light in a different point.

In the image above, you can see a magnifying glass focus all the light rays that come from the sun into one spot.

What kind of materials do you think we make lenses out of? Pick all the options you think are correct.

You can select multiple answers

Here is an example of a ray diagram for a magnifying glass.

The key features you need to remember are the principal focus (sometimes called **** "focal point") and the focal length.

True or false? The focal length is the distance between the lens and the principal focus.

The principal focus is the point where all parallel rays that hit the lens will converge

Its location depends on the refractive index of the material of the lens.

In this case is the image 'enlarged' or 'diminished'?

Is the image 'upright' or 'inverted'?

Pick the correct statement.

What does inverted mean?

Here is a ray diagram for a different kind of lens. Is the image 'enlarged', 'diminished' or the 'same size'?

Is the image 'upright' or 'inverted'?

Let's recap!

Lenses refract light and create images. A ray diagram for a lens includes ...

a principal axis and a lens, the principal focus of the lens, and the focal length.

Images formed by a lens can be either ...

enlarged, diminished or the same size or upright or inverted.