Scanning microscope is used to look at cell structure with 10 nm resolution. A beam of electrons from a hot filament is accelerated to 50,000 km/s and then focussed to a small spot on the specimen. What is the wavelength in nanometers of the beam of incoming electrons?

The focal length of a relaxed human eye is approximately 1.7 cm. when we focus our eyes on a close up object, we can change the refractive power of the eye by about 16 diopters. (a) does the refractive power of our eyes increase or decrease by 16 diopters when we focus closely? explain. (b) calculate the focal length of the eye when we focus closely.

Gasoline comes from petroleum, which is made from ancient living things. petroleum, therefore, contains a type of energy. a. heat b. nuclear c. biological d. chemical potential

In science and physics what is the standard unit of measure for speed?