The greenhouse effect occurs because carbon dioxide in the atmosphere absorbs __________ radiation.
Fill in the blank(s) with correct word
[Ques. 2] The ozone layer absorbs __________ radiation from sunlight.
Fill in the blank(s) with correct word
[Ques. 3] The ionosphere reflects __________ frequency radio waves.
Fill in the blank(s) with correct word
[Ques. 4] Three devices that use electromagnetic induction in their operation are __________, __________, and __________.
Fill in the blank(s) with correct word
[Ques. 5] The direction of a magnetic field at a point can be determined by __________.
Fill in the blank(s) with correct word
[Ques. 6] Greenhouse gasses include
a. water vapor. b. CO2.
c. CO. d. methane.
[Ques. 7] Which recording formats employ magnetism?
a. videotape b. CD
c. DVD d. floppy disk
[Ques. 8] What makes an ordinary bar magnet magnetic?
a. Electrons inside it are themselves tiny magnets.
b. The magnetic fields of electrons in the magnet are aligned and add together.
c. It contains magnetic charges.
d. none of the above
[Ques. 9] EM waves in a vacuum travel at a speed
a. of c.
b. varying with their wavelength.
c. varying with their intensity.
d. of 299,792,458 m/s.
[Ques. 10] A magnetic field will be produced at a point in space if an electric field at that point
a. exists.
b. gets stronger.
c. gets weaker.
d. changes direction.
e. all of the above
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