Cover Test. While there are many ways for your eye doctor to check how your eyes work together, the cover test is the simplest and most common. During a cover test, your eye doctor will ask you to focus on a small object across the room and will then cover each of your eyes alternately while you stare at the target.
Hooke's Law states that the restoring force of a spring is directly proportional to a small displacement. In equation form, we write. F = -kx. where x is the size of the displacement.
Hooke's Microscope Hooke's drawing of Cork Cells. 1670: Antonie van Leeuwenhoek (1632-1723) described cells in a drop of pond water using a microscope. A Dutch businessman and a contemporary of Hooke. He also used microscopes and was a physicist. He made his own fine quality lens for use in monocular microscopes and was the first person to observe bacteria and protozoa. Some of his lenses could magnify objects 250X.