How are electromagnetic waves used in a bar-code scanner?
A. An image is produced when a silicon chip releases electrons by
the photoelectric effect.
B. Visible light iS reflected off an object and then captured by a
charge-coupled device.
C. X-rays shine on objects, and the rays either pass through or are
absorbed by the objects.
D. Red light shines on a bar code, and light is reflected according to
the black-and-white pattern.