Question

question 10 of 10
what are two reasons why a home computer scanner requires electromagnetic waves to operate?
a. red light shines on patterns of black and white, producing a pattern from the reflected light.
b. visible light needs to reflect off an object and be captured by a charge - coupled device.
c. the charge - coupled device contains a silicon chip that releases electrons by the photoelectric effect, producing an image.
d. x - rays are needed to either pass through or be absorbed by the objects they contact.

Explanation:

• For option B: Home computer scanners use visible light (an electromagnetic wave). The light reflects off the object (e.g., a document). The charge - coupled device (CCD) then captures this reflected light. The CCD is a key component in converting the light information into an electronic signal.
• For option C: The silicon chip in the CCD operates based on the photoelectric effect. When light (an electromagnetic wave) hits the silicon, it causes electrons to be released. These electrons are then processed to form an image.

• Option A: Red light is a type of visible light (so it is an electromagnetic wave), but the description is too simplistic. It doesn't mention the key role of the charge - coupled device and the photoelectric effect in detail.
• Option D: X - rays are not used in home computer scanners. Home scanners use visible light, not X - rays (which are used in medical imaging and other specialized applications).

Answer:

B. Visible light needs to reflect off an object and be captured by a charge - coupled device.
C. The charge - coupled device contains a silicon chip that releases electrons by the photoelectric effect, producing an image.