Q&A Hero

Physic

Q: The greenhouse effect occurs because carbon dioxide in the atmosphere absorbs ultraviolet radiation.
Q: The ozone layer absorbs infrared radiation from sunlight.
Q: The ionosphere reflects high frequency radio waves.
Q: An electric motor can be manually turned and made to act as a generator.
Q: A speaker can be used as a crude microphone.
Q: A transformer only works with AC.
Q: Three devices that use electromagnetic induction in their operation are generators, transformers, and dynamic microphones.
Q: One can reverse the north and south poles of an electromagnet by reversing the direction of current flow through it.
Q: The shape of the magnetic field around a bar magnet is very close to the shape of the electric field around a single positive charge.
Q: Moving electric charges make magnetic fields.
Q: A stationary electric charge produces a magnetic field around it.
Q: There are positive and negative magnetic charges, analogous to positive and negative electric charges.
Q: The direction of a magnetic field at a point can be determined by a compass.
Q: The deviation from the way a compass needle points from the true north direction is the magnetic declination.
Q: What is the temperature (to one decimal place and in degrees K) for radiation that has a maximum wavelength (max) of 3.5 x 10-6 m?
Q: 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?
Q: (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?
Q: (a) What is the frequency of an EM wave that has a wavelength of 1 millimeter? (b) What type of EM wave is this?
Q: A radio transmitter broadcasts at a frequency of 200,000 Hz. What is the wavelength of the wave?
Q: Match each item with the correct statement below.a. blackbody radiation i. magnetic fieldb. carbon dioxide j. microwavesc. electromagnetic induction k. ozoned. gamma rays l. radio wavese. greenhouse effect m. transformerf. infrared n. ultravioletg. ionosphere o. x raysh. lodestone1/ its direction at a point is indicated by a compass2/ generators and dynamic microphones utilize this3/ low frequency radio waves reflect off this4/ absorbs ultraviolet light in sunlight5/ radar utilizes this6/ a naturally occurring ferromagnetic substance7/ the highest frequency electromagnetic waves8/ the main form of radiation that our bodies emit9/ works with AC but not with DC10/ causes skin to tan11/ occurs because carbon dioxide blocks infrared but not visible light12/ only the very lowest frequencies of these waves can penetrate ocean water
Q: The auxiliary power unit (APU) on a jetliner is a generator and operates on the principle of __________________
Q: Modern aircraft weather radars operate in the _____________ portion of the EM spectrum.
Q: The radio waves used to communicate with astronauts in space must be ___________ frequency waves.
Q: TV remote controls use ________ radiation.
Q: A superconductor expels any magnetic field from its interior. This is called __________.
Q: 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 __________.
Q: 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 __________.
Q: 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.
Q: 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 __________.
Q: The peak of a body's blackbody radiation curve shifts upward as the temperature of the body __________.
Q: The peak of a body's blackbody radiation curve shifts toward longer wavelength as the temperature of the body __________.
Q: As the temperature of a body increases the color of the body shifts from __________ to __________.
Q: 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.
Q: As the temperature of an object increases, the wavelength of the brightest light emitted __________.
Q: NARRBEGIN: Body emitting blackbodyFor a body emitting blackbody radiation, the total power emitted is proportional to the 4th power of the body's absolute temperature:(Tin kelvins)and the wavelength of the emitted EM radiation that has the highest intensity is inversely proportional to the body's absolute temperature according to:( in meters, Tin kelvins)Assume an object is emitting blackbody radiation.NARRENDIf the Kelvin temperature of an object is doubled, the amount of radiant energy emitted each second is __________ the original amount.
Q: The wavelength of a radio wave from an AM station broadcasting at 1,000 kilohertz on your radio dial is __________.
Q: If we see two objects that have different colors, the light waves coming from them have different ____________
Q: __________ are emitted when high speed electrons decelerate as they are smashed into a metal target.
Q: Lower frequency radio waves are reflected back to earth by the ______________.
Q: The type of EM radiation that has wavelength just a bit longer than that of visible light is __________.
Q: The type of EM radiation that has wavelength just a bit shorter than that of visible light is __________.
Q: __________ radiation causes your skin to tan.
Q: The type of EM wave having the highest frequency is __________.
Q: The type of EM waves used in radar is __________.
Q: A glowing blackbody that appears bluish in color is __________ than one that appears reddish.
Q: The total radiant power emitted by a blackbody is proportional to its _________________ raised to the fourth power.
Q: __________ radiation is emitted from a small hole in a furnace.
Q: The main form of radiation that our bodies emit is __________.
Q: The increase in the amount of carbon dioxide in the atmosphere is responsible for __________.
Q: The greenhouse effect occurs because carbon dioxide in the atmosphere absorbs __________ radiation.
Q: The ozone layer absorbs __________ radiation from sunlight.
Q: The ionosphere reflects __________ frequency radio waves.
Q: Three devices that use electromagnetic induction in their operation are __________, __________, and __________.
Q: The direction of a magnetic field at a point can be determined by __________.
Q: Greenhouse gasses includea. water vapor b. CO2 c. COd. methane
Q: Which recording formats employ magnetism?a. videotape b. CD c. DVDd. floppy disk
Q: 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
Q: NARRBEGIN: Body emitting blackbodyFor a body emitting blackbody radiation, the total power emitted is proportional to the 4th power of the body's absolute temperature:(Tin kelvins)and the wavelength of the emitted EM radiation that has the highest intensity is inversely proportional to the body's absolute temperature according to:( in meters, Tin kelvins)Assume an object is emitting blackbody radiation.NARRENDAs the temperature of a body increases, the peak of its blackbody radiation curvea. shifts toward longer wavelengthb. shifts toward shorter wavelengthc. shifts upwardd. shifts downwarde. doesn"t change
Q: EM waves in a vacuum travel at a speeda. of cb. varying with their wavelengthc. varying with their intensityd. of 299,792,458 m/s
Q: A magnetic field will be produced at a point in space if an electric field at that pointa. existsb. gets strongerc. gets weakerd. changes directione. all of the above
Q: The direction of the force on an electric charge in a magnetic field isa. in the direction of the magnetic fieldb. in the direction of motion of the chargec. perpendicular to the magnetic fieldd. perpendicular to the direction of motion of the chargee. none of the above
Q: The type of EM wave used in aircraft radar isa. radio waves b. microwaves c. X-raysd. gamma rays
Q: The type of radiation affected by greenhouse gasses isa. UV radiation b. IR radiation c. visible radiationd. gamma radiation
Q: The ionosphere reflectsa. microwaves b. AM radio waves c. FM radio wavesd. X-rays
Q: 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 b. 215.9 c. 864.5d. 1,113,123
Q: The magnetic compass in an aircraft point to the ______________ pole.a. magnetic north b. magnetic south c. geographic northd. geographic south
Q: Making a digital recording of a sound involvesa. analog-to-digital conversion b. digital-to-analog conversion c. electromagnetic wavesd. all of the above
Q: A current can be made to flow in a wire ifa. it is connected to a batteryb. it is put into motion near a magnetc. a magnet is put into motion near itd. all of the above
Q: 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 becausea. the coil acts like a transformerb. the free electrons in the conductor experience a force when they move in the magnetic fieldc. an electromagnetic wave is generatedd. the wire is ferromagnetice. none of the above
Q: 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 becausea. the coil acts like a transformerb. the changing magnetic field induces an electric field in the wirec. an electromagnetic wave is generatedd. the wire is ferromagnetice. none of the above
Q: What does "IR" stand for?a. ultraviolet b. muon neutrino c. high frequencyd. infrared
Q: The cosmic background radiationa. has a blackbody spectrumb. has its peak emission in the microwave bandc. corresponds to a blackbody at a temperature of 2.726 kelvinsd. all of the above
Q: The cosmic background radiationa. has a blackbody spectrumb. has its peak emission in the microwave bandc. corresponds to a blackbody at a temperature of 2.726 kelvinsd. all of the above
Q: About how hot does something have to get to glow red hot?a. 375 degrees F b. 800 degrees F c. 3000 Kd. 6000 K
Q: 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
Q: 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
Q: As the temperature of a body increases,a. the body gets brighterb. the color of the body shifts from red to whitec. the wavelength of the most intense light decreasesd. the frequency of the most intense light increasese. all the above
Q: 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. a. 1/16th b. half c. the same as d. 2 times e. 16 times
Q: As the temperature of an object increases, the wavelength of the brightest light emitted a. increases b. decreases c. doesn"t change d. depends on the composition of the body e. depends on the size of the body
Q: NARRBEGIN: Body emitting blackbodyFor a body emitting blackbody radiation, the total power emitted is proportional to the 4th power of the body's absolute temperature:(Tin kelvins)and the wavelength of the emitted EM radiation that has the highest intensity is inversely proportional to the body's absolute temperature according to:( in meters, Tin kelvins)Assume an object is emitting blackbody radiation.NARRENDIf the Kelvin temperature of an object is doubled, the amount of radiant energy emitted each second is ____________ the original amount.a. 1/16thb. halfc. the same asd. 2 timese. 16 times
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