Computer Science for IGCSE & O level - Hardware (Section 12 - No. 9)
What does the text state happens if the barcode is first read by a red laser or LED?
The barcode is illuminated.
The laser reflects off the barcode.
The laser scans the barcode.
The barcode is read by a camera.
解释
The text states that the laser will reflect off the barcode when first read by a red laser.