okay i am not understanding these so if you could answer them and explain them to me as well that would be great thanks! you dont have to go in to deep details but some explaining would be nice thanks.
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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