c.
the wavelength of the most intense light decreases
d.
the frequency of the most intense light increases
e.
all the above
37. A body in a room at 300 K is heated to 3,000 K. The amount of energy radiated each second
by the body increases by a factor of
a.
10
b.
100
c.
1,000
d.
10,000
e.
100,000
38. A body in a room at 300 K is heated to 3,000 K. The wavelength of the most intense EM
radiation emitted by the body at 3,000 K is the wavelength of the most intense EM radiation
at 300 K.
a.
0.0001 times
b.
0.1 times
c.
the same as
d.
10 times
e.
10,000 times
39. About how hot does something have to get to glow red hot?
a.
375 degrees F
c.
3000 K
b.
800 degrees F
d.
6000 K
40. The cosmic background radiation
a.
has a blackbody spectrum
b.
has its peak emission in the microwave band
c.
corresponds to a blackbody at a temperature of 2.726 kelvins
d.
all of the above
41. The cosmic background radiation
a.
has a blackbody spectrum
b.
has its peak emission in the microwave band
c.
corresponds to a blackbody at a temperature of 2.726 kelvins
d.
all of the above
42. What does “IR” stand for?
a.
ultraviolet
c.
high frequency
b.
muon neutrino
d.
infrared
43. A coil of wire is connected to a galvanometer. When a bar magnet is moved in and out of
the coil, the galvanometer records a current. The current results because
a.
the coil acts like a transformer
b.
the changing magnetic field induces an electric field in the wire
c.
an electromagnetic wave is generated
d.
the wire is ferromagnetic
e.
none of the above
44. A coil of wire is connected to a galvanometer. When the coil is rotated in a magnetic field,
the galvanometer records a current. The current results because
a.
the coil acts like a transformer
b.
the free electrons in the conductor experience a force when they move in the
magnetic field
c.
an electromagnetic wave is generated
d.
the wire is ferromagnetic
e.
none of the above
45. A current can be made to flow in a wire if
a.
it is connected to a battery
b.
it is put into motion near a magnet
c.
a magnet is put into motion near it
d.
all of the above
46. Making a digital recording of a sound involves
a.
analog-to-digital conversion
c.
electromagnetic waves
b.
digital-to-analog conversion
d.
all of the above
47. The magnetic compass in an aircraft point to the ______________ pole.
a.
magnetic north
c.
geographic north
b.
magnetic south
d.
geographic south
48. An object at an initial temperature of 27 oC is raised to a temperature of 877 oC. How much
more energy does the object emit as blackbody raidation at the higher temperature compared
to the lower temperature?
a.
32.5
c.
864.5
b.
215.9
d.
1,113,123
49. The ionosphere reflects
a.
microwaves
c.
FM radio waves
b.
AM radio waves
d.
X-rays
50. The type of radiation affected by greenhouse gasses is
a.
UV radiation
c.
visible radiation
b.
IR radiation
d.
gamma radiation
51. The type of EM wave used in aircraft radar is
a.
radio waves
c.
X-rays
b.
microwaves
d.
gamma rays
MULTIPLE RESPONSE
1. The direction of the force on an electric charge in a magnetic field is
a.
in the direction of the magnetic field
b.
in the direction of motion of the charge
c.
perpendicular to the magnetic field
d.
perpendicular to the direction of motion of the charge
e.
none of the above
2. 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
3. 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
4. As the temperature of a body increases, the peak of its blackbody radiation curve
a.
shifts toward longer wavelength
b.
shifts toward shorter wavelength
c.
shifts upward
d.
shifts downward
e.
doesn’t change
5. 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
6. Which recording formats employ magnetism?
a.
videotape
c.
DVD
b.
CD
d.
floppy disk
7. Greenhouse gasses include
a.
water vapor
c.
CO
b.
CO2
d.
methane
COMPLETION
1. The direction of a magnetic field at a point can be determined by __________.
2. Three devices that use electromagnetic induction in their operation are __________,
__________, and __________.
3. The ionosphere reflects __________ frequency radio waves.
4. The ozone layer absorbs __________ radiation from sunlight.
5. The greenhouse effect occurs because carbon dioxide in the atmosphere absorbs
__________ radiation.
6. The increase in the amount of carbon dioxide in the atmosphere is responsible for
__________.
7. The main form of radiation that our bodies emit is __________.
8. __________ radiation is emitted from a small hole in a furnace.
9. The total radiant power emitted by a blackbody is proportional to its _________________
raised to the fourth power.
10. A glowing blackbody that appears bluish in color is __________ than one that appears
reddish.
11. The type of EM waves used in radar is __________.
12. The type of EM wave having the highest frequency is __________.
13. __________ radiation causes your skin to tan.
14. The type of EM radiation that has wavelength just a bit shorter than that of visible light is
__________.
15. The type of EM radiation that has wavelength just a bit longer than that of visible light is
__________.
16. Lower frequency radio waves are reflected back to earth by the ______________.
17. __________ are emitted when high speed electrons decelerate as they are smashed into a
metal target.
18. If we see two objects that have different colors, the light waves coming from them have
different ____________
19. The wavelength of a radio wave from an AM station broadcasting at 1,000 kilohertz on your
radio dial is __________.
20. If the Kelvin temperature of an object is doubled, the amount of radiant energy emitted each
second is __________ the original amount.
21. As the temperature of an object increases, the wavelength of the brightest light emitted
__________.
22. If the Kelvin temperature of a body is doubled, the wavelength of the most intense light is
__________ the wavelength originally of the most intense light.
23. As the temperature of a body increases the color of the body shifts from __________ to
__________.
24. The peak of a body’s blackbody radiation curve shifts toward longer wavelength as the
temperature of the body __________.
25. The peak of a body’s blackbody radiation curve shifts upward as the temperature of the
body __________.
26. A body in a room at 300 K is heated to 3,000 K. The amount of energy radiated each second
by the body increases by __________.
27. A body in a room at 300 K is heated to 3,000 K. The wavelength of the most intense EM
radiation emitted by the body at 3,000 K is __________ times the wavelength of the most
intense EM radiation at 300 K.
28. A coil of wire is connected to a galvanometer. When a bar magnet is moved in and out of
the coil, the galvanometer records a current. The current results because of __________.
29. A coil of wire is connected to a galvanometer. When the coil is rotated in a magnetic field,
the galvanometer records a current. The current results because of __________.
30. A superconductor expels any magnetic field from its interior. This is called __________.
31. TV remote controls use ________ radiation.
32. The radio waves used to communicate with astronauts in space must be ___________
frequency waves.
33. Modern aircraft weather radars operate in the _____________ portion of the EM spectrum.
34. The auxiliary power unit (APU) on a jetliner is a generator and operates on the principle of
__________________
MATCHING
Match each item with the correct statement below.
a.
blackbody radiation
i.
magnetic field
b.
carbon dioxide
j.
microwaves
c.
electromagnetic induction
k.
ozone
d.
gamma rays
l.
radio waves
e.
greenhouse effect
m.
transformer
f.
infrared
n.
ultraviolet
g.
ionosphere
o.
x rays
h.
lodestone
1. its direction at a point is indicated by a compass
2. generators and dynamic microphones utilize this
3. low frequency radio waves reflect off this
4. absorbs ultraviolet light in sunlight
5. radar utilizes this
6. a naturally occurring ferromagnetic substance
7. the highest frequency electromagnetic waves
8. the main form of radiation that our bodies emit
9. works with AC but not with DC
10. causes skin to tan
11. occurs because carbon dioxide blocks infrared but not visible light
12. only the very lowest frequencies of these waves can penetrate ocean water
PROBLEM
1. A radio transmitter broadcasts at a frequency of 200,000 Hz. What is the wavelength of the
wave?
2. (a) What is the frequency of an EM wave that has a wavelength of 1 millimeter? (b) What
type of EM wave is this?
3. (a) What is the wavelength of the peak of the blackbody radiation curve for something at
3,000 kelvins (the temperature of the filament of a light bulb)? (b) What type of EM wave
is this?
4. A transformer is designed to step down the 120V line voltage to 9V. If there are 400 turns
on the input coil, how many turns should there be on the output coil?
5. What is the temperature (to one decimal place and in degrees K) for radiation that has a
maximum wavelength ( max) of 3.5 10-6 m?