Theodore maiman demonstrated the first working laser in 1960. at that time, scientists didn't really know what they were going to use the lasers for, but since then, there have been many new products developed that rely on laser technology. in which of the following products are lasers used? i. cd players ii. barcode scanners iii. hair removal iv. medical surgery

i, ii, iii and iv

Explanation:

Lasers are optical devices used to produce beam of light by the stimulated emission of radiation. As a matter of fact, Laser is the short form for "Light amplification by stimulated emission of radiation". Lasers can be used in various applications such as;

i. laser printers

ii. fiber optic and free-space optical communication

iii. medical surgery and

iv. treatments of skin

v. barcode scanners

vi. hair removal from face, leg, arm and other areas

vii. optical disk drives e.g in CD players

work: w = fd (given)

work done by chet   =50*1 = 50 j

work done by mika =40*2 = 80 j

work done by sara =30*1.5 = 45 j

work done by bill =60*0.5 = 30 j

students in order from the greatest amount of work done to the least is mika> chet> sara> bill

hence option (b) is correct.

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