___21. Light with the lowest frequency or longest wavelength detected by your eyes is perceived as _____.

a. Orange

b. Green

c. Blue

d. Red

____22. The waves produced by heat lamps are _____.

a. Microwaves

b. Mechanical

c. Infrared

d. X-rays

_____23. Waves that can be used to examine internal body parts are ____.

a. Radio waves

b. Visible light

c. Ultraviolet

d. X-rays

_____24. A device that produces a narrow beam light of one wavelength is a _____.

a. Microwave oven

b. Radar

c. Laser

d. TV

____25. Microwaves are used in all of the following ECEPT in _______.

a. Communications

b. Surgery

c. Ovens

d. Radars

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