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When astronauts aboard the space shuttle look down at the earth, its atmosphere appears blue. Why?
-The molecules of air act as mirrors that only reflect blue light.
-The molecules of air have resonances that deflects short-wavelength light in all directions.
The molecules of air have resonances that deflects all wavelengths of light equally in all directions.
-The molecules of air have resonances that deflects long-wavelength light in all directions.
The molecules of air have resonances that deflects short-wavelength light in all directions.
If you shine a flashlight horizontally at a glass full of water, the glass will redirect the light beam. How?
-The light bends as it enters and leaves the glass.
-The light refracts as it enters and leaves the glass.
-The light changes speed as it enters and leaves the glass. -All of the above choices are correct.
All of the above choices are correct.
Diamond has an index of refraction of 2.42. If you put a diamond in water, you see reflections from its surfaces. However, if you put it in a liquid with an index of refraction of 2.42, the diamond is invisible. Why is it invisible, and how is this effect useful to a jeweler or gemologist?
-If the liquid and diamond have the same index of refraction, then light doesn't change speed on entry to or exit from the diamond and all light reflects from the interface between the two.
-If the liquid and diamond have the same index of refraction, then light changes speed on entry to or exit from the diamond and all light reflects from the interface between the two.
-If the liquid and diamond have the same index of refraction, then light doesn't change speed on entry to or exit from the diamond and no light reflects from the interface between the two.
-If the liquid and diamond have the same index of refraction, then light changes speed on entry to or exit from the diamond and no light reflects from the interface between the two.
If the liquid and diamond have the same index of refraction, then light doesn't change speed on entry to or exit from the diamond and no light reflects from the interface between the two.
What colors of light does red paint absorb?
-Red and green.
-Red and blue.
-Red.
-Green and blue.
Green and blue.
If you illuminate red paint with pure blue light, what color will that paint appear?
-White.
-Red.
-Blue.
-Black.
Black.
While a sodium atom is in its ground state, it cannot emit light. Why not?
-There is no lower energy state to which it can make a transition to emit a photon.
-Sodium atoms can never emit photons.
-There are no higher energy states to which it can make a transistion to emit a photon.
-All of the above choices are correct.
There is no lower energy state to which it can make a transition to emit a photon.
A discharge in a mixture of gases is more likely to emit a full white spectrum of light than a discharge in a single gas. Why?
-The more different atoms and molecules present in a mixture of gases, the less variety there is in the possible radiative transitions and thus, the more likely that a full spectrum of white light will be emitted by the discharge.
-The variety of possible radiative transitions is independent of the mixture of gases and thus, the spectrum of light emitted will be identical to a discharge in a single gas.
-The more different atoms and molecules present in a mixture of gases, the more variety there is in the possible radiative transitions and thus, the more likely that a full spectrum of white light will be emitted by the discharge.
-It depends on the mixture of gases.
The more different atoms and molecules present in a mixture of gases, the more variety there is in the possible radiative transitions and thus, the more likely that a full spectrum of white light will be emitted by the discharge.
Why does increasing the current passing through an LED affect the brightness of its light?
-With more current passing through the LED, the population of electrons in excited conduction states decreases and the rate of radiative transition in the LED increases.
-With more current passing through the LED, the population of electrons in excited conduction states increases and the rate of radiative transition in the LED increases.
-With more current passing through the LED, the population of electrons in excited conduction states decreases and the rate of radiative transition in the LED decreases.
-With more current passing through the LED, the population of electrons in excited conduction states increases and the rate of radiative transition in the LED decreases.
With more current passing through the LED, the population of electrons in excited conduction states increases and the rate of radiative transition in the LED increases.
If electrons had four different internal states that could be distinguished from one another, how many electrons could occupy the same orbital without violating the Pauli exclusion principle?
-4 electrons
-any number from 4 to 8 electrons
-any number from 0 to 4 electrons
-any number from 0 to 8 electrons
any number from 0 to 4 electrons
If electrons were not Fermi particles, any number of them could occupy a particular orbital. How would these electrons tend to arrange themselves among the orbitals in an atom?
-The electrons would occupy 1S orbital.
-The electrons would evenly occupy all S orbitals.
-The electrons would tend to evenly occupy all possible orbitals.
-The electrons would evenly occupy all S and P orbitals.
The electrons would occupy 1S orbital.
Is the p-type half of a p-n junction electrically neutral, positive, or negative?
-Negative.
-Positive.
-Neutral.
Negative.
Which is true in comparing red and blue light?
-Red light has a shorter wavelength and lower frequency than blue light.
-Red light has a longer wavelength and higher frequency than blue light.
-Red light has a longer wavelength and lower frequency than blue light.
-Red light has a shorter wavelength and higher frequency than blue light.
Red light has a shorter wavelength and lower frequency than blue light.
In a rainbow,
-the red light travels slower in water than the violet light does, so the violet light bends more.
-the red light travels slower in water than the violet light does, so the red light bends more.
-the red light travels faster in water than the violet light does, so the red light bends more.
-the red light travels faster in water than the violet light does, so the violet light bends more.
the red light travels faster in water than the violet light does, so the violet light bends more.
What is not a disadvantage of incandescent light bulbs?
-Most of the radiation they emit is infrared, not visible.
-The light they emit is too red as compared to sunlight.
-They emit too much ultraviolet radiation.
-They do not emit enough blue light as compared to sunlight.
They emit too much ultraviolet radiation
When does an atom emit a photon?
-When it transitions from an excited state
-When it transitions from the ground state to an excited state.
-When it transitions from an excited state to a lower-energy excited state.
-When it transitions from an excited state to a higher-energy excited state.
When it transitions from an excited state to a lower-energy excited state.
What is an LED?
-Luminescent Electric Diode
-Light Emitting Device
-Light Enhancing Device
-Light Emitting Diode
Light Emitting Diode
What is true about laser light?
-The light results from spontaneous emission and is incoherent.
-The light results from spontaneous emission and is coherent.
-The light results from stimulated emission and is coherent.
-The light results from stimulated emission and is incoherent.
The light results from stimulated emission and is coherent.
Light passing from air into a denser transparent medium will
-speed up.
-slow down.
-not change speed.
-Not enough information is given to determine.
slow down.
Which answer has the colors in order from the shortest wavelength to the longest?
-Red Green Blue
-Red Blue Green
-Blue Red Green
-Blue Green Red
Blue Green Red
Which answer has the colors in order from the lowest energy to the highest?
-Red Green Blue
-Red Blue Green
-Blue Red Green
-Blue Green Red
Red Green Blue
Which answer has the colors in order from the lowest frequency to the highest?
-Red Blue Green
-Blue Red Green
-Blue Green Red
-Red Green Blue
Red Green Blue
Light travels at about 300 million meters per second, and the Sun is about 150 million kilometers from the Earth. How long does it take light from the Sun to reach Earth?
-0.5 seconds
-2 seconds
-8 minutes
-80 minutes
8 minutes
What effect causes the sky to appear blue?
-Rayleigh scattering
-Dispersion
-Impedance mismatch
-Destructive Interference
Rayleigh scattering
What effect causes rainbows?
-Rayleigh scattering
-Dispersion and total internal reflection
-Impedance mismatch
-Destructive Interference
Dispersion and total internal reflection
Soap bubbles have their beautiful colors when illuminated with white light because
-of dispersion.
-the light interferes within the bubble.
-the light rays reflecting off the top and bottom surfaces interfere.
-light rays reflecting off the bottom mix and interfere with each other.
the light rays reflecting off the top and bottom surfaces interfere.
You are standing at the shore of a calm lake, trying to look beneath its surface. All you see is a strong reflectionof the sky overhead. But when you put on polarizing sunglasses, the glare almost disappears and you can see fish swimming under the surface of the water. If you turn your head sideways, so that the sunglass lenses are rotated 90° from before, the glare will
-become even dimmer but the fish will disappear altogether so that it is not an improvement.
-reappear.
-become even dimmer but the fish will also become dimmer so that it's not an improvement.
-remain almost absent.
reappear.
Ultraviolet light causes damage to your skin while infrared light does not because
-ultraviolet light has a longer wavelength than infrared light.
-ultraviolet light has more photons than infrared light.
-a photon of ultraviolet light carries much more energy than a photon of infrared light.
-ultraviolet light is more intense than infrared light.
a photon of ultraviolet light carries much more energy than a photon of infrared light.
The colors that you see when sunlight strikes a cut crystal wineglass or a cut diamond are a result of the fact that two light waves with
-different wavelengths travel at different speeds in most materials.
-the same wavelength in air can have different frequencies in a material.
-the same frequency in air can have different wavelengths in a material.
-the same wavelengths can have different colors.
different wavelengths travel at different speeds in most materials.
Light passing from air into empty space will
-speed up.
-slow down.
-not change speed.
-Not enough information is given to determine.
speed up.
Light travels at about 300 million meters per second, and it takes light 100,000 years to go from one end of our galaxy to the other. How many miles across is our galaxy?
-100,000 m
-300,000,000 m
-9.3×10²⁰ m
-9.3×10²⁰ km
9.3×10²⁰m
A laser light beam can travel much farther than a flashlight without spreading out because laser light
-has high energy.
-is monochromatic.
-is coherent.
-is polarized.
is coherent.
In what way is light from a sodium vapor lamp unlike sunlight?
-It is created because something is hot (luminescing).
-It is monochromatic.
-It has too much blue.
-It has too much red.
It is monochromatic.
"Laser" stands for
-light amplification through stimulated emission of radiation.
-light attenuation through stimulated emission of radiation.
-light amplification through spontaneous emission of radiation
-let's all study electromagnetic waves and refraction
light amplification through stimulated emission of radiation.
The tubes in fluorescent lamps have a white powder on their inner surfaces. This powder
-slows down the white light produced by the gas atoms inside the tube so that less of that white light reflects as it passes through the walls of the tube.
-conducts electricity from one electrode to the other and emits visible light as current passes through it.
-absorbs ultraviolet light and uses the energy from that light to produce visible light.
-scatters the white light produced by the gas atoms inside the tube so that it is both vertically and horizontally polarized and doesn't cause glare.
absorbs ultraviolet light and uses the energy from that light to produce visible light.
A particular light photon carries an energy of 4.3 x 10⁻¹⁹ J. What are the frequency, wavelength, and color of this light?
v= 648958647751282.82 Hz
𝝀=462 nm
color = blue
Radio waves travel through empty space
A) Faster than visible light
B) Slower than visible light
C) At the speed of visible light
D) With only electric fields and not magnetic fields
C) At the speed of visible light
Imagine being an observer watching a light wave travel by you, much like you would watch a car travel by you on the highway. If you could detect the electric field at your location, you would observe
A) the electric field remaining constant because light does not carry charge.
B) the electric field undulating to the right or left as the wave travels to the right or left.
C) the electric field undulating up and down as the wave travels to the right or left.
D) no electric field at all.
C) the electric field undulating up and down as the wave travels to the right or left.
The speed of light is about
A) 300 million miles per hour.
B) 300 million kilometers per hour.
C) 300 million meters per second.
D) 300 thousand meters per second.
C) 300 million meters per second.
The speed of light is roughly 300,000,000 m/s. A radio station has frequency 100 megahertz. What is the station’s wavelength?
A) 30,000,000,000 meters
B) 3,000,000 meters
C) 3.0 meters
D) 0.33 meters
C) 3.0 meters
What type of circuit is used to tune a radio?
A) Radio circuit
B) Antenna circuit
C) Tank circuit
D) Inductance circuit
C) Tank circuit
If an electric field wave oscillates north and south, and the wave is traveling straight up, then what direction does the magnetic field wave oscillate?
A) East and west
B) North and south
C) Up and down
D) It does not oscillate: this situation is impossible
A) East and west
What does “AM” stand for?
A) AMplification
B) Antenna Modulation
C) Antenna Modification
D) Amplitude Modulation
D) Amplitude Modulation
One way radio waves do not differ from visible light is that
a) There will never be a movie named “Visible Light”.
b) Radio waves have less energy and travel slower than visible light.
c) Radio waves have less energy and travel faster than visible light
d) Radio waves travel at the same speed as visible light.
d) Radio waves travel at the same speed as visible light.
Microwaves have
A) shorter wavelengths than visible light
B) comparable wavelengths to visible light
C) longer wavelengths than visible light
D) no wavelength at all
C) longer wavelengths than visible light
Microwaves have
A) lower frequencies than visible light
B) comparable frequencies to visible light
C) higher frequencies than visible light
D) no frequency at all
A) lower frequencies than visible light
Compared to the radio waves used in normal radio broadcasts, the microwaves used for satellite transmissions have
A) higher frequencies and shorter wavelengths.
B) higher frequencies and longer wavelengths.
C) lower frequencies and shorter wavelengths.
D) lower frequencies and longer wavelengths.
A) higher frequencies and shorter wavelengths.
Microwaves have speeds
A) greater than visible light.
B) less than visible light.
C) equal to visible light.
D) 55 miles per hour; it’s still the law.
C) equal to visible light.
Light passing from air into a denser transparent medium will
A) speed up.
B) slow down.
C) not change speed.
D) Not enough information is given to determine.
B) slow down.
Which answer has the colors in order from the shortest wavelength to the longest?
A) Red Green Blue
B) Red Blue Green
C) Blue Red Green
D) Blue Green Red
D) Blue Green Red
Which answer has the colors in order from the lowest energy to the highest?
A) Red Green Blue
B) Red Blue Green
C) Blue Red Green
D) Blue Green Red
A) Red Green Blue
Light travels at about 300 million meters per second, and the Sun is about 150 million kilometers from the Earth. How long does it take light from the Sun to reach Earth?
A) ~0.5 seconds
B) ~2 seconds
C) ~8 minutes
D) ~80 minutes
C) ~8 minutes
What effect causes rainbows?
A) Reflection
B) Dispersion
C) Impedance
D) Interference
B) Dispersion
Ultraviolet light causes damage to your skin while infrared light does not because
A) ultraviolet light has a longer wavelength than infrared light.
B) ultraviolet light has more photons than infrared light.
C) a photon of ultraviolet light carries much more energy than a photon of infrared light.
D) ultraviolet light is more intense than infrared light.
C) a photon of ultraviolet light carries much more energy than a photon of infrared light.
Light passing from water into empty space will
A) speed up.
B) slow down.
C) not change speed.
D) Not enough information is given to determine.
A) speed up.
Light travels at about 300 million meters per second, and it takes light 100,000 years to go from one end of our galaxy to the other. How many meters across is our galaxy?
A) 100,000 m
B) 300,000,000 m
C) 9.4 x 10²⁰ m
D) 9.4 x 10²⁰ km
C) 9.4 x 10²⁰ m
A laser light beam can travel much farther than a flashlight without spreading out because laser light
A) has high energy .
B) is monochromatic.
C) is coherent.
D) is polarized.
C) is coherent.
What colors are the eye’s color-sensing cells most sensitive to?
A) Red, yellow, and blue
B) Orange, green, and violet
C) Red, green, and violet
D) Red, green, and blue
D) Red, green, and blue
Light is emitted when electrons
A) disappear and then reappear.
B) jump down in energy level.
C) jump up in energy level.
D) turn into positrons
B) jump down in energy level.
“LASER” stands for
A) light amplification through stimulated emission of radiation.
B) light attenuation through stimulated emission of radiation.
C) light amplification through spontaneous emission of radiation
D) let’s all study electromagnetic waves and refraction.
A) light amplification through stimulated emission of radiation.
Laser light is
A) polarized.
B) coherent.
C) incoherent.
D) incandescent.
B) coherent.
Three different lasers are emitting steady beams of light. Each beam consists of countless copies a single original photon of light. However, not all colors can be emitted by a laser. Which of the following choices is possible for these three lasers?
A) Yellow, green, and blue light
B) Green, blue, and red light
C) Blue, white, and yellow light
D) White, yellow, and green light
B) Green, blue, and red light
The tubes in fluorescent lamps have a white powder on their inner surfaces. This powder
A) slows down the white light produced by the gas atoms inside the tube so that less of that white light reflects as it passes through the walls of the tube.
B) conducts electricity from one electrode to the other and emits visible light as current passes through it.
C) absorbs ultraviolet light and uses the energy from that light to produce visible light.
D) scatters the white light produced by the gas atoms inside the tube so that it is both vertically and horizontally polarized and doesn't cause glare
C) absorbs ultraviolet light and uses the energy from that light to produce visible light.
“LED” stands for
A) light emitting device
B) light emitting diode
C) light electromagnetic device
D) light electric diode
B) light emitting diode
LED light is not damaging to your eye like a laser can be because
A) laser light is coherent while LED light is not.
B) laser light is monochromatic while LED light is not.
C) laser light is polarized.
D) laser light travels faster.
A) laser light is coherent while LED light is not.
Which one of the following lists gives the correct order of the electromagnetic spectrum from low to high frequencies?
A) radio waves, infrared, microwaves, ultraviolet, visible, x-rays, gamma rays
B) radio waves, microwaves, infrared, visible, ultraviolet, x-rays, gamma rays
C) radio waves, microwaves, visible, x-rays, infrared, ultraviolet, gamma rays
D) radio waves, ultraviolet, x-rays, microwaves, infrared, visible, gamma rays
E) radio waves, infrared, x-rays, microwaves, ultraviolet, visible, gamma rays
B) radio waves, microwaves, infrared, visible, ultraviolet, x- rays, gamma rays
What do we mean when we say that two light rays striking a screen are in phase with each other?
A) They have the same wavelength.
B) When the electric field due to one is a maximum, the electric field due to the other is also a maximum, and this relation is maintained as time passes.
C) They are traveling at the same speed.
D) They alternately reinforce and cancel each other.
B) When the electric field due to one is a maximum, the electric field due to the other is also a maximum, and this relation is maintained as time passes.
Two light sources are said to be coherent if they are
A) of the same amplitude, and maintain a constant phase difference.
B) of the same frequency and amplitude.
C) of the same frequency.
D) of the same frequency, and maintain a constant phase difference
D) of the same frequency, and maintain a constant phase difference
Imagine being an observer watching a light wave travel by you, much like you would watch a car travel by you on the highway. If you could detect the electric field at your location, you would observe
A) the electric field undulating up and down as the wave travles to the right or left.
B) no electric field at all.
C) the electric field undulating to the right or left as the wave travels to the right or left.
D) the electric field remaining constant because light does not carry charge
A) the electric field undulating up and down as the wave travles to the right or left.
For a beam of light, the direction of polarization is defined as
A) the direction of the electric field's vibration.
B) the direction that is perpendicular to both the electric and magnetic field vectors.
C) the direction of the magnetic field's vibration.
D) the beam's direction of travel
A) the direction of the electric field's vibration.
If you put an egg in a microwave oven, it will become very hot. But if you put a dehydrated egg (a dried egg containing no water) in the microwave oven, the egg will not be affected because
A) microwaves transfer heat to food principally through its water molecules
B) the dehydrated egg is too dry to have a temperature. Only foods containing water or oil can actually become hot
C) the dehydrated egg reflects the microwaves while the normal egg does not
D) the dehydrated egg is much less dense than a normal egg and doesn't conduct heat well
A) microwaves transfer heat to food principally through its water molecules
Which one of the following is not an electromagnetic wave?
A) radio waves
B) sound waves
C) gamma rays
D) infrared
E) ultraviolet.
B) sound waves
Diamond has an index of refraction of 2.42. If you put a diamond in water, you see reflections from its surfaces. However, if you put it in a liquid with an index of refraction of 2.42, the diamond is invisible. Why is it invisible, and how is this effect useful to a jeweler or gemologist?
A) If the liquid and diamond have the same index of refraction, then light doesn't change speed on entry to or exit from the diamond and no light reflects from the interface between the two.
B) If the liquid and diamond have the same index of refraction, then light changes speed on entry to or exit from the diamond and all light reflects from the interface between the two.
C) If the liquid and diamond have the same index of refraction, then light changes speed on entry to or exit from the diamond and no light reflects from the interface between the two.
D) If the liquid and diamond have the same index of refraction, then light doesn't change speed on entry to or exit from the diamond and all light reflects from the interface between the two.
A) If the liquid and diamond have the same index of refraction, then light doesn't change speed on entry to or exit from the diamond and no light reflects from the interface between the two.
If the Sun were to disappear at this moment, we wouldn't know about it for
A) 8 minutes.
B) 8 seconds.
C) 7 seconds, reflex time.
D) 8 hours.
A) 8 minutes.
Light passing from air into a denser transparent medium will
A) speed up
B) no change in speed
C) slow down
D) Not enough information is given to determine
C) slow down
The tubes in fluorescent lamps have a white powder on their inner surfaces. This powder
A) absorbs ultraviolet light and uses the energy from that light to produce visible light
B) slows down the white light produced by the gas atoms inside the tube so that less of that white light reflects as it passes through the walls of the tube
C) scatters the white light produced by the gas atoms inside the tube so that it is both vertically and horizontally polarized and doesn't cause glare
D) conducts electricity from one electrode to the other and emits visible light as current passes through it
A) absorbs ultraviolet light and uses the energy from that light to produce visible light
When an electron jumps from an orbit where n = 4 to one where n = 2
A) a photon is emitted.
B) two photons are emitted.
C) a photon is absorbed.
D) two photons are absorbed.
E) None of the given answers are correct.
A) a photon is emitted.
While a sodium atom is in its ground state, it cannot emit light. Why not?
A) There is no lower energy state to which it can make a transition to emit a photon
B) There are no higher energy states to which it can make a transistion to emit a photon.
C) Sodium atoms can never emit photons.
D) All of the above choices are correct.
A) There is no lower energy state to which it can make a transition to emit a photon
How far does a beam of light travel in 2.5 seconds?
A) 7.5 × 10⁵ m
B) 7.5 m
C) 90 m
D) 70 m
E) 7.5 × 10⁸m
E) 7.5 × 10⁸m
Your cell phone exchanges voice and data information with a nearby base station using microwaves. Those microwaves are transmitted and received by radio antennas and they propagate from transmitter to receiver much like the microwaves in a microwave oven. Suppose you are talking to someone on your cell phone and the microwave your phone is transmitting has a frequency of 1870 MHz (1.870 GHz). What is the wavelength of that microwave?
A) The microwave's wavelength is 5.61 cm.
B) The microwave's wavelength is 16.0 cm.
C) The microwave's wavelength is 18.7 cm.
D) The microwave's wavelength is 5.35 cm
B) The microwave's wavelength is 16.0 cm.
A certain part of the electromagnetic spectrum ranges from 200 nm to 400 nm. What is the highest frequency associated with this portion of the spectrum?
A) 1.50 × 10¹⁴Hz
B) 7.50 × 10¹⁴ Hz
C) 1.50 × 10¹⁵ Hz
D) 7.50 × 10¹³ Hz
E) 7.50 × 10¹⁵ Hz
C) 1.50 × 10¹⁵ Hz
How far does a beam of light travel through space in one 365-day year?
A) 30 × 10⁸ m
B) 20 × 10¹⁴ m
C) 95 × 10¹⁴ m
D) 95 × 10¹⁵ m
E) 80 × 10¹² m
C) 95 × 10¹⁴ m
The yellow light from a sodium vapor lamp has a frequency of 5.08 × 10¹⁴ Hz. How much energy does each photon of that light carry?
A) 1.31× 10⁻¹⁶J
B) 3.37× 10⁻¹⁸ J
C) 1.31× 10⁻¹⁵ J
D) 3.37× 10⁻¹⁹ J
D) 3.37× 10⁻¹⁹ J
A particular light photon carries an energy of 3.8 × 10⁻¹⁹ J. What is the wavelength of this light?
A) 5.2× 10⁻⁷ m
B) 5.2× 10⁻⁹m
C) 11.4 × 10⁻⁷ m
D) 11.4 × 10⁻⁹ m
A) 5.2× 10⁻⁷ m
The ignition system of an automobile produces sparks to ignite the fuel in the engine. During each spark process, charges suddenly accelerate through a spark plug wire and across a spark plug's narrow gap. Sometimes this process introduces noise into your radio reception. Why?
The sun emits a stream of energetic electrons and protons called the solar wind. These particles frequently get caught up in the earth's magnetic field, traveling in spiral paths that take them toward the north or south magnetic poles. When they head northward and collide with atoms in the earth's upper atmosphere, those atoms emit light we know as the aurora borealis, or northern lights. These particles also interfere with radio reception. Why do they emit radio waves?
A) The spiraling electric charges are accelerating and thus producing constant electric and magnetic fields which results in the charges emitting electromagnetic waves.
B) The spiraling electric charges are moving steadily and thus producing changing electric and magnetic fields which results in the charges emitting electromagnetic waves.
C) The spiraling electric charges are moving steadily and thus producing constant electric and magnetic fields which results in the charges emitting electromagnetic waves.
D) The spiraling electric charges are accelerating and thus producing changing electric and magnetic fields which results in the charges emitting electromagnetic waves.
The spiraling electric charges are accelerating and thus producing changing electric and magnetic fields which results in the charges emitting electromagnetic waves.
Although a particular AM radio station claims to transmit 50,000 W of music power, that's actually its average power. There are times when it transmits more power than that and times when it transmits less. Explain.
A) The power being transmitted is changed in order to represent air pressure fluctuations with the radio wave: both compressions and rarefactions are represented by weakening the radio wave.
B) The power being transmitted is changed in order to represent air pressure fluctuations with the radio wave: compressions are represented by weakening the radio wave and rarefactions are represented by strengthening the radio wave.
C) The power being transmitted is changed in order to represent air pressure fluctuations with the radio wave: compressions are represented by strengthening the radio wave and rarefactions are represented by weakening the radio wave.
D) The power being transmitted is changed in order to represent air pressure fluctuations with the radio wave: both compressions and rarefactions are represented by strengthening the radio wave.
C) The power being transmitted is changed in order to represent air pressure fluctuations with the radio wave: compressions are represented by strengthening the radio wave and rarefactions are represented by weakening the radio wave.
When your receiver is too far from an AM radio station, you can only hear the loud parts of the transmission. When it's too far from an FM station, you lose the whole sound all at once. Explain the reasons for this difference.
A) In both AM and FM transmissions, the radio wave intensity is constant.
B) In an AM transmission, the radio wave intensity is constant but in an FM transmission, the radio wave is strongest during the loudest portions of the broadcast.
C) In an AM transmission, the radio wave is strongest during the loudest portions of the broadcast but in an FM transmission, the radio wave intensity is constant.
D) In both AM and FM transmissions, the radio wave is strongest during the loudest portions of the broadcast.
C) In an AM transmission, the radio wave is strongest during the loudest portions of the broadcast but in an FM transmission, the radio wave intensity is constant.
Porous, unglazed ceramics can absorb water and moisture. Why are they unsuitable for use in a microwave oven?
-Water molecules trapped in the ceramics would absorb microwaves and the ceramic would become extremely hot.
-Water molecules trapped in the ceramics would turn and bump into one another over and over again because of the fluctuating electric field of the microwave and the ceramic would become extremely hot.
-Water molecules trapped in the ceramics would convert the energy of the microwaves into thermal energy and the ceramic would become extremely hot.
-All of the above
all of the above
Why is it so important that a microwave oven turn off when you open the door?
Releasing the microwaves into the room wouldn't be healthy.
When you're listening to FM radio near buildings, reflections of the radio wave can make the reception particularly bad in certain locations. Compare this effect to the problem of uneven cooking in a microwave oven.
A) Both involve constructive interference in electromagnetic waves.
B) The FM transmission involves constructive interference and the microwave oven involves destructive interference in electromagnetic waves.
C) The FM transmission involves destructive interference and the microwave oven involves constructive interference in electromagnetic waves.
D) Both involve destructive interference in electromagnetic waves.
D) Both involve destructive interference in electromagnetic waves.
An extremely fast-moving charged particle traveling in a magnetic field can radiate X-rays, a phenomenon known as synchrotron radiation. Why is the magnetic field essential to this emission?
Without the magnetic field, the charged particle would travel at constant velocity (at constant speed along a straight path) and would not radiate electromagnetic waves.
The frequency of the radio wave emitted by a cordless telephone is 960 MHz. What is the wavelength of that wave?
0.312284 m
The frequency of the radio wave emitted by a cordless telephone is 920 MHz. What is the wavelength of that wave?
0.326 m
Citizens band (CB) radio uses radio waves with frequencies near 22 MHz. What are the wavelengths of these waves, and how long should a quarter-wavelength CB antenna be?
λ = 13.62693 m
the length of CB antenna is 3.4067325 m
The electromagnetic waves in blue light have frequencies near 4 ×10¹⁴ Hz. What are their wavelengths?
λ ≈ 0.000000749481 m
What did James Clerk Maxwell discover in 1865?
-A changing electric field produces a changing magnetic field.
-A changing electric field produces a magnetic field.
-An electric field produces a changing magnetic field.
-An electric field produces a magnetic field.
-A changing electric field produces a magnetic field.
Radio waves are electromagnetic waves that have
-high frequencies and short wavelengths.
-low frequencies and short wavelengths.
-low frequencies and long wavelengths.
-high frequencies and long wavelengths.
-low frequencies and long wavelengths.
FM stands for
-frequency modification.
-functional modification.
-functional modulation.
-frequency modulation.
-frequency modulation.
If the wavelength of an electromagnetic wave decreases,
-the speed of the wave increases.
-the frequency of the wave decreases.
-the frequency of the wave increases.
-the speed of the wave decreases.
-the frequency of the wave increases.
Radio waves travel through empty space
-faster than visible light.
-slower than visible light.
-at the speed of visible light.
-with only electric fields and not magnetic fields.
-at the speed of visible light.
Note
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