Question

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

Explanation:

• Option A: Visible light (an electromagnetic wave) reflects off the object. The charge - coupled device (CCD) captures this reflected light. The CCD is a key component in scanners for converting light into an electrical signal.
• Option D: The charge - coupled device has a silicon chip. When light (electromagnetic wave) hits the silicon chip, the photoelectric effect occurs (electrons are released). This process helps in creating an image as the released electrons are processed to form a digital representation of the scanned object.
• Option B: Home computer scanners do not specifically use only red light for scanning in the way described. They can use a range of visible light.
• Option C: X - rays are not used in home computer scanners. X - rays are typically used in medical imaging (e.g., X - ray machines in hospitals) and some industrial non - destructive testing, not in common home scanner operations.

Answer:

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