AQA GCSE Physics Unit 3 - Mirrors and Lenses

Plane mirror - forms an image that is:

• virtual
• the same size as the object
• upright
• laterally inverted

Convex mirror forms an image that:

• appears to be formed at a single point behind the mirror
• is smaller than the object
• is virtual
• is upright

Concave mirror forms an image depending on the distance of the object from the mirror. it always forms an image inside its curve where all the rays of light converge. This is called the focal point.

If the distance between the object and the mirror is less than the distance between the mirror and the focal point (F), the image produced is:

• virtual
• upright
• larger than the object

If the distance between the object and the mirror is greater than the distance between the mirror and the focal point, then the image produced is:

• inverted (upside down)
• laterally inverted
• real (the rays of light actually meet)
• of varying size, depending on the distance from the mirror (the greater the distance, the smaller the object)

There are two types of lens:

• diverging (concave)
• converging (convex)

A diverging lens refracts rays of light outwards so they appear to have come from one point, the focus (F). Only a ray which meets the lens at 90 degrees will pass straight through the lens. The image produced by a diverging lens is:

• virtual
• upright

A converging lens refracts rays of light inwards at the two curved boundaries so they meet at the focus. Like a diverging lens, only the ray which meets the lens at 90 degrees will pass straight through the lens. The image produced by the lens depends on the distance of the object from the lans.

If the distance between the object to the lens is less than the distance from the lens to the focal point, then the image produced is:

• virtual
• upright
• enlarged

If the distance between the object and the lens is greater than the distance from the lans to the focal point then the image produced is:

• real
• inverted
• laterally inverted

*used in a camera*