Just wonderin if anyone can do these all perfect i think its imposible?

1 . Which phrase best describes electromagnetic waves? A. They have no wavelength. B. They transfer energy. C. They require a medium. D. The frequency equals the wavelength. 2 . Which electromagnetic waves have the shortest wavelength? A. light B. radio C. X-rays D. gamma rays 3 . Which waves have... show more 1 . Which phrase best describes electromagnetic waves?

A. They have no wavelength.
B. They transfer energy.
C. They require a medium.
D. The frequency equals the wavelength.

2 . Which electromagnetic waves have the shortest wavelength?

A. light
B. radio
C. X-rays
D. gamma rays

3 . Which waves have wavelengths slightly longer than those of light?

A. radio waves
B. UV radiation
C. infrared radiation
D. X-rays

4 . Evidence that light behaves as a wave comes from

A. refraction.
B. reflection.
C. diffraction.
D. interference.

5 . Besides radio waves, what other waves are commonly used in communications?

A. gamma rays
B. microwaves
C. infrared radiation
D. UV radiation

6 . What do objects that contain heat emit?

A. radio waves
B. infrared radiation
C. gamma rays
D. microwaves

7 . What process changes radio waves into electrical signals?

A. diffraction
B. radiation
C. modulation
D. refraction

8 . Which of the following is the most penetrating kind of electromagnetic radiation?

A. UV rays
B. microwaves
C. X-rays
D. gamma rays

9 . Sunscreen is used to protect the skin from what type of radiation?

A. UV
B. infrared
C. radio waves
D. X-rays

10 . What part of the earth's atmosphere protects us from harmful radiation?

A. stratosphere
B. ionosphere
C. ozone layer
D. hemisphere

11 . Which type of electromagnetic wave causes skin cells to produce vitamin D?

A. visible light
B. UV waves
C. infrared waves
D. X-rays

12 . Which of the following best describes X-rays?

A. long wave length, low frequency
B. long wave length, high frequency
C. short wave length, low frequency
D. short wave length, high frequency

13 . What is changed in an AM radio's carrier wave?

A. frequency
B. wavelength
C. speed
D. amplitude

14 . What two types of fields create electromagnetic waves?

A. electric and magnetic
B. atomic and gravitational
C. radiation and magnetic
D. electrical and kinetic

15 . What must vibrate to produce an electromagnetic wave?

A. electrons
B. electric charges
C. magnetic fields
D. radiant energy

16 . The speed of electromagnetic waves in a vacuum is

A. 3 × 108 m/s.
B. 3 × 1010 m/s.
C. 3× 10–8 m/s.
D. 3 × 106 m/s.

17 . Albert Einstein explained that light can behave as a particle called a

A. electron.
B. proton.
C. photon.
D. neutron.

18 . A microwave oven excites what type of molecules?

A. oxygen
B. water
C. hydrogen
D. carbon dioxide

19 . Which of the following is a device that uses radio waves to find the position and movement of objects?

A. radar
B. sonar
C. MRI
D. CAT

20 . In FM radio broadcasting, what is changed in the carrier wave?

A. amplitude
B. frequency
C. speed
D. wavelength
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