BYU Physics Sem 2 review
Which of the following best describes "complementary" colors?
two colors that will form white light when mixed
What is a wave?
A disturbance which transfers energy from one location to another
What is a magnetic domain?
A group of magnetically aligned atoms
What is the cause of the aurora borealis and aurora australis?
Charged particles from the sun are deflected by Earth's magnetic field and emit light
What statement describes compressions and rarefactions?
Compressions: areas where the medium is gathered together. Rarefactions: areas where the medium is spread apart
What kind of lenses do telescopes and microscopes primarily use?
Concave
Which diagram shows light refracting in a concave lens
Concave is symmetrical, light rays going through bend according to the shape of the lens
How are ions formed?
Ions are formed by either adding or removing electrons from an atom
What must remain constant during the operation of a transformer?
Power (voltage x current)
What does it mean for an electron to be in an excited state?
The electron absorbs energy and move to a higher-energy orbital
What happens when an electron moves from an unstable state to a stable state
The electron emits a photon of the energy corresponding to the difference between the two states
What is an atomic spectrum?
The energies emitted by excited electrons returning to their ground state.
Which of the following best describes the critical angle?
The minimum angle where none of the light beam escapes a medium
Why do our eyes have a blind spot in them?
The nerves form a tight bundle that cannot sense light
a stream of electrons moves horizontally to the right. In what direction is positive electric current
left
What determines which element an atom is?
number of protons
what is an ampere of current
one coulomb of charge flowing past a point in one second
A virtual image is one that
only appears to have light rays that converge
A convex lens is capable of producing what kind of images
real or virtual
Which list gives of visible light in correct order from shortest to longest wavelength?
blue, green, yellow
Gravitational and electrical forces are similar in each of the following ways, except
both forces can either attract or repel
Which type of radiation is the easiest to block?
alpha
Why do current-carrying wires deflect compass needles?
Moving charges produce magnetic fields of their own
Why do current-carrying wires interact with magnetic fields?
Moving charges produce magnetic fields of their own
If the image distance is equal to the object distance, what is the magnification of the image?
1.0
Mass of proton
1.00728
Mass of neutron
1.00867
What is the speed of light in diamond?
1.24E8 m/s
1 u=
1.6605E-27
What is the wavelength range of typical human hearing? Use air medium for speed
16.5-0.0165m
How many magnetic poles do all magnets have
2
What is the speed of light in water?
2.26E8 m/s
What is the frequency range of typical human hearing?
20Hz-20,000Hz
What is the speed of sound in air?
330m/s
What is the speed of light?
3x10^8
What is the speed of electromagnetic waves in a vacuum?
3x10^8 m/s
What is the half life of carbon 14?
5700
how many joules does a 60-watt light bulb use in sixty seconds
60J
The sun is 1.5x10^11 m from Earth. How long does it take light to reach Earth from the Sun?
8.3 minutes
Which number is the value of a light year?
9,500,000,000,000,000 m
What is an electrical generator
A device that converts mechanical energy into electricity the way a motor works but in reverse
What is an electromagnet?
A magnet produced by current in a wire wrapped around an iron core
What is loudness or volume of a sound wave?
A physical reaction to the intensity of sound waves
What is a rarefaction in a sound wave?
A place where the molecules of the medium are spread furthest apart
What does a neutron decay into?
A proton and an electron
What are the three main types of naturally occurring nuclear radiation?
Alpha, beta, gamma
What do electromagnetic waves consist of?
Alternating electric and magnetic fields spreading through space
What is resonance?
Alternating pushes and pulls by sound waves cause a vibration in any object.
In old western movies, an outlaw is often seen putting his ear to the train tracks to determine whether a train is coming. Explain why this would be a better method than just standing still and listening and looking carefully.
Assuming that the railroad is made of a material such as steel, the speed of sound through steel (5940 m/s) is faster than air (330 m/s). Therefore, the sound would travel faster through the railroad than the air.
Describe the basic structure of all atoms
Atoms all have a nucleus made up of protons and neutrons, and are surrounded by electrons.
Where do images seen in plane mirrors appear?
Behind the mirror an equal distance as the object
Describe what the critical angle is
Best answers include the description that the critical angle is only meaningful for waves passing from an area of higher index into an area of lower index of refraction. The angle relative to the normal will be greater in the lower index. The critical angle is the angle within the higher index medium so that when the wave exits into the lower index medium the light bends so that it is directly along the surface between the two mediums.
Describe how to find the equivalent resistance of a parallel circuit.
Best answers include the idea that resistors in parallel must be added as reciprocals. 1/Rtotal = 1/R1 + 1/R2 + 1/R3 + ... In other words, find the reciprocal of each resistor, add those values, and take the reciprocal of the result to get R total
Explain why concave lenses are often called diverging lenses
Best responses include the ideas that concave lenses cause light to refract in a way that as the light passes through the lens it comes out on the other side bent towards the center line or axis of the lens.
Describe what happens in beta decay
Best response include the idea that beta decay occurs in a nucleus to adjust the energy and force balance within the nucleus. A neutron transforms into a proton and an electron. The electron is ejected from the nucleus, and the nucleus now has one more proton, so it is a different atom than it was before.
What is refraction?
Best responses define refraction as the bending of a wave as it passes from one medium into another. The frequency of the wave remains constant but the speed is different in different mediums so the wavelength changes causing the wave to change direction of travel.
Define transparent, translucent, and opaque
Best responses include the definitions that transparent means that waves pass through the medium relatively undisturbed, translucent means that waves pass through the medium but they are distorted as they do so, and opaque means that the waves are blocked by the medium.
Describe the differences between fission and fusion.
Best responses include the descriptions that fission occurs when a nucleus breaks into one or more parts and releases energy. Fission occurs naturally on Earth. Fusion occurs when two nuclei come together and combine into a new nucleus. Fusion occurs only at high temperatures and pressures like those found in the sun.
What are isotopes?
Best responses include the explanation that isotopes are atoms of the same element (same number of protons) that have different numbers of neutrons in the nucleus.
How do concave lenses correct nearsightedness and convex lenses correct farsightedness?
Best responses include the explanation that nearsightedness is caused because light focuses in the eye too soon or too far in front of the retina. Concave lenses cause light to diverge and this can cause the light in the eye to focus on the retina. Farsightedness is the opposite of nearsightedness—light focuses too late or behind the retina. A convex lens causes light to converge and can cause light in the eye to focus sooner than it would on the retina.
Describe the basic operation of an electrical power generation plant
Best responses include the following processes of using some form of movement to cause a turbine to spin. A turbine is essentially a fan blade that spins when water or steam or wing moves past it. The turbine is connected to a shaft that spins a coil of wire through a magnetic field whenever the turbine spins. Rotating the wire coil in a magnetic field induces an electrical current in the wire.
Describe what happens in alpha decay
Best responses include the idea that alpha decay occurs when a large nucleus cannot be held together by the strong force. An alpha particle of two protons and two neutrons (a helium nucleus) breaks away from the parent nucleus and is ejected from it. The parent nucleus is a different atom. 1 of 1
What is a limitation of carbon-14 dating?
Best responses include the idea that carbon-14 can only be used on organic materials. Also, the margin of error is about 15%, so precise measurements are very difficult to make.
What is constructive interference of waves?
Best responses include the idea that constructive interference occurs when two (or more) waves overlap in such a way that their amplitudes add to and reinforce each other.
What is destructive interference of waves?
Best responses include the idea that destructive interference occurs when two (or more) waves overlap in such a way that their amplitudes subtract from and cancel each other out
The text states that all protons, electrons, and neutrons are the same, regardless of the type of atom they are found in. What determines the different types of atoms found in nature?
Best responses include the idea that different types of atoms contain different numbers of protons, neutrons, and electrons. Ideas not included in the text that may also be included: (1) the number of protons determines the elemental type of atom (e.g., oxygen, iron, and gold), (2) different numbers of neutrons attached to the same number of protons make isotopes of the same element, and (3) different numbers of electrons orbiting the nucleus make ions of the same element.
What is diffraction
Best responses include the idea that diffraction is the bending of a wave around a barrier or through an opening. The wave does not change medium, so it does not change speed or wavelength. The opening must be of a physical size on par with the wavelengths passing through it or diffraction will not occur.
Describe how to find the equivalent resistance of a series circuit
Best responses include the idea that resistors in parallel are simply added together. Rtot = R1 + R2 + R3 + ...
What observation led scientists to conclude that there are two types of electrical charge?
Best responses include the idea that scientists observed repulsion and attraction between electrically charged objects and deduced that two basic units of charge must exist to produce those effects.
Your car has lights that appear yellow. if you look closely, they are often made from regular light bulbs with a yellow film attached over the,. Why do these lights appear yellow when lit up
Best responses include the idea that the yellow-colored film absorbs all other colors but yellow, allowing yellow wavelengths to pass through
Describe the main differences between mechanical and electromagnetic waves
Best responses include the ideas that a wave transfers mechanical energy through a disturbance of a medium. The wave travels through the medium, but the medium itself stays in place. The wave makes the molecules of the medium vibrate back and forth in place. Waves can also transfer electromagnetic energy through changes in electrical and magnetic fields. The fields can create forces on charged particles and do not require a medium to travel through.
How do designers of auditoriums utilize interference of sound waves in their designs?
Best responses include the ideas that auditoriums are designed to produce reflections in many different directions increasing the opportunities for constructive interference.
What are the similarities and differences of gravitational and electric forces?
Best responses include the ideas that both forces obey the inverse square law, both can produce acceleration, and both are long-range forces. Differences are that electrical forces can both attract and repel, while gravitational forces only attract. Also, the electrical force is nearly 20 orders of magnitude larger than gravitational force, all other things being equal
Explain the main differences between conductors, insulators, semiconductors, and superconductors
Best responses include the ideas that conductors have many electrons that are relatively loosely bound to their respective atoms' nucleus, making it easy for electrons to move from atom to atom, thus producing electric current. The electrons in insulators, by contrast, are tightly bound to their atoms and prevent movement; thus no electric current flows. Semiconductors are typically made of materials that are insulators when pure but that have varying degrees of conductivity when impurities are mixed in. Superconductors are a special class of materials that exhibit nearly zero resistance to the flow of electricity under special circumstances, typically at very low temperatures.
Explain why convex lenses are often called converging lenses
Best responses include the ideas that convex lenses cause light to refract in a way that as the light passes through the lens it comes out on the other side bent away from the center line or axis of the lens
Describe how electromagnetic waves are formed
Best responses include the ideas that electromagnetic waves are formed when charged particles accelerate due to either an electrical field or a magnetic field or both. The accelerating charge creates both electric and magnetic field.
What is electromotive force?
Best responses include the ideas that electromotive force is the electric pressure or force that causes electrons to flow in a conductor. It is the same thing as electric potential or voltage.
what are some similarities and differences between magnetic poles and electric charges
Best responses include the ideas that for both things opposites attract and likes repel. North attracts south but repels north. Positive attracts negative but repels positive. One important difference is that all magnets always have exactly two poles, one north and one south. Individual north or south poles have not been observed in nature.
Explain the main features of a parallel circuit
Best responses include the ideas that in a parallel circuit the current will split and flow through different components. There are multiple pathways for current so a portion of the total will pass through each component in the different paths (Kirchoff's current law). The voltage will drop across each component can be determined using Ohm's law and the current for that particular pathway.
Describe the photoelectric effect
Best responses include the ideas that light can cause electrons to be ejected from their atoms. This only occurs if the light has exactly the right amount of energy. Brighter, more intense light of the wrong energy (frequency and wavelength) will not cause any electron to be ejected. Even the dimmest light of the correct energy will cause one or more electrons to be ejected. This is strong evidence that light is a particle.
What is the dual nature of light?
Best responses include the ideas that light exhibits properties of both waves and particles. Light exhibits wave properties such as interference, refraction, frequency, and wavelength. Light also exhibits particle properties, most notably the photoelectric effect, which cannot be explained by wave behavior.
Briefly describe how light becomes polarized.
Best responses include the ideas that light is polarized because the electrons producing the EM waves vibrate in a particular direction (vertical, horizontal, etc.). When light reflects from a surface, it can become polarized in the direction parallel to the surface.
What are some distinguishing characteristics between electromagnetic waves and mechanical waves?
Best responses include the ideas that mechanical waves require a medium to move in, electromagnetic waves can travel through a medium but also can travel without one.
What are some of the drawbacks of using nuclear fuel in electrical energy generation plants?
Best responses include the ideas that nuclear fuel produces waste materials that are also radioactive but that cannot be used as fuel, waste materials are radioactive for many hundreds or thousands of years, safe disposal or storage of waste materials is difficult, and nuclear power plants are very expensive to build and operate safely.
What are some of the benefits of using nuclear fuel in electrical energy generation plants?
Best responses include the ideas that nuclear plants themselves are non-polluting, a large amount of energy is released for a relatively small amount of fuel, and dependence on shrinking fossil fuels reserves is reduced.
What are the distinguishing features of real vs. virtual images formed by mirrors and lenses?
Best responses include the ideas that real images are formed where actual reflected of refracted rays are seen. The light rays actually meet at that point. Virtual images are formed where reflected or refracted light is perceived to have come from by our brains tracing the rays that are seen back to a point where the light did not actually meet. Real images can be cast onto a screen. Virtual images can only be seen by looking into the mirror or through the lens. Either kind of image as formed by a lens is essentially the same as the same type of image as formed by a mirror.
What are red shift and blue shift?
Best responses include the ideas that red shift and blue shift refer to the observed shift towards longer of shorter wavelengths of atomic spectra when the observed object is moving towards or away from the observer. Red shift occurs when the observed object is moving away from us; the atomic spectrum of the elements is shifted to longer wavelengths. Blue shift is the opposite.
Why are sunsets often red?
Best responses include the ideas that sunlight must travel further through the atmosphere at sunset. Blue light is scattered early in the journey through the atmosphere. The longer red wavelengths travel further through the atmosphere to the sunset observer
How are atomic spectrums related to the Doppler effect?
Best responses include the ideas that the Doppler effect describes the observed lengthening or shortening of wavelengths when objects move relative to each other. Similar shifts are observed in EM waves and are called red shift or blue shift.
Describe how the Doppler effect occurs
Best responses include the ideas that the Doppler effect occurs when a sound source and a sound receiver (for example a person listening to an emergency siren) move relative to each other. If they move towards each other, the receiver will hear the sound at a higher pitch than actual. If they move away from each other, the pitch will sound lower than actual.
You and a friend are at opposite ends of a very long tunnel. You cannot see each other because the tunnel is too long. Steel pipes run along the wall between you. If your friends shouts very loudly and bangs on the pipes with a hammer, identify which sound you will hear first and explain why.
Best responses include the ideas that the sound created by pounding on the steel pipes will be heard first because sound travels in steel much faster than it travels through air.
Describe how the nucleus of atoms is held together
Best responses include the ideas that the strong nuclear force counteracts the repulsion of the electrical force. The strong force acts only over very small distances like the diameters of a few protons. Large nuclei are bigger than just a few protons and would be pushed apart by electrical repulsion; neutrons help keep the distances between protons ideal for the strong force but not the electrical force.
Describe the basic operation of a transformer
Best responses include the ideas that transformers operate by electromagnetic induction. Voltage and current are supplied to a coil of wire wrapped around an iron core like an electromagnet. The current in the coil produces an electric field. This is the primary coil. A second coil is also wrapped around the same iron core. The magnetic field produced by the primary coil induces a current to flow in the secondary coil and a corresponding voltage to be created. The induced voltage and current are proportional to the ratio of the number of windings in the primary and secondary coils.
Describe the main difference between transverse and longitudinal waves
Best responses include the ideas that transverse waves vibrate at right angles to the direction that the waves travel. Water waves are a common example. In longitudinal waves the medium vibrates back and forth in the same direction as the waves travel. A spring that is squashed together in one place and released quickly often produces a longitudinal wave.
In summers, dark cars with dark interiors are often much hotter than white cars with light interiors. Explain why
Best responses include the ideas that white reflects more colors from the entire visible spectrum and therefore will absorb less energy from sunlight than darker colors will. Darker colors, on the other hand, absorb almost all wavelengths and the energy they contain. Dark cars will experience a greater rise in temperature than light cars.
Why would the gravitational force be smaller than the electric force all other factors being equal?
Best responses will acknowledge that the forces are very different in magnitude because of the physical constant (G or k) associated with each type of force.
What are some advantages Newton's reflecting telescope had over Galileo's refracting telescope?
Best responses will include the ideas that Newton's telescope was easier to construct. Because it used a mirror, which was better able to support its own weight than a lens, Newton's telescope could be built with a larger diameter, allowing it to collect more light. Newton's telescope also had a longer effective distance between the objective and eyepiece lenses.
Describe how a magnetic compass works
Best responses will include the ideas that magnetic compasses work because a small magnet that is free to rotate will naturally align itself with the magnetic field of another magnet. Earth is a giant magnet and magnetic compasses align themselves to Earth's magnetic field.
Which produces more voltage in an electrical generator, moving a magnet through the coils of wire or moving coils of wire past a magnetic field?
Both are equally effective
What is electromagnetic induction?
Creating current by moving wires through magnetic fields
Which mirror is a converging mirror
Crescent moon shaped with points facing left
Which mirror is a diverging mirror?
Crescent moon, with points facing right
Which of the following waves travels the fastest?
Infrared, radio waves, and ultraviolet waves all travel at the same speed, since they are all EM waves
What describes a benefit of Earth's magnetic field?
Earth's magnetic field shields the surface from harmful radiation from the sun
Which of the following scientists did not attempt to calculate the speed of light?
Einstein; Michelson, Galileo, Huygens all did however
A beat frequency of 4Hz is observed when two sound waves interfere. One wave is known to have a frequency of 112Hz. What is the frequency of the other wave?
Either 108Hz or 116Hz
According to the fundamental rule of charges, which of the following statements must be true?
Electrons and protons must attract one another
What does beta radiation consist of?
Electrons ejected from the nucleus
When you rub your feet on the carpet, what happens?
Electrons transfer from the carpet to you and you gain a small negative charge
Faraday and Henry worked closely together on the discovery that current could be made by moving a magnet into or out of a coil of wire
False: they each made the discovery independently, but at the same time
In the photoelectric effect shining a bright, more intense red light causes greater numbers of electrons with greater energy to be freed
False; red light is lower energy than other visible light. if it does not have enough energy to eject one electron, brighter red light will not eject any electrons either. If the red light does have energy sufficient to eject electrons, although more electrons may be ejected, brighter light will not give them more energy
How are the angle of incidence and the angle of reflection measured?
From a line perpendicular to the reflecting surface
A convex lens has a focal length of 6cm. An object is placed 4cm from the lens, and you look through the lens at the object. Where will the object appear to be, and what will be the magnification?
Given: f = +6cm (convex lens means positive value for f), do = +4cm. These values give di = -12cm and M = +3. The image is virtual as seen in the diagram and as given by the negative sign for di. The image is upright compared to the object and enlarged in size. This can be seen in the diagram and from magnification being positive and greater than 1.
A concave lens has a focal length of 5cm. An object is placed 7cm from the lens, and you look through the lens at the object. Where will the object appear to be, and what will be the magnification?
Given: f = -5cm (concave lens means negative value for f), do = +7cm. These values give di = -2.92cm and M = 0.42. The image is virtual as seen in the diagram and as given by the negative sign for di. The image is upright compared to the object and reduced in size. This can be seen in the diagram and from magnification being positive and smaller than 1.
What makes an atom electrically neutral?
Having equal numbers of protons and electrons
What does gamma radiation consist of?
High energy photons ejected from the nucleus
How can we change the strength of an electromagnet?
Increased current, more coils
How can the voltage of an electric generator be changed
Increasing the number of coils of wire, increasing the speed of the magnetic field lines moving past the wire
What advantage does knowing about the atomic spectrum give astronomers?
It helps them determine what elements make up stars
What happens to the atomic number of an atom when a beta particle is emitted?
It increases by one
How long would it take a radio signal to reach a star that is 9 light years away?
It would take nine years
In what units is electrical energy measured
Kilowatt-hours
Which of the following best describes the dual nature of light?
Light can be thought of as behaving like a particle or like a wave
What is the fundamental rule of charges?
Like charges repel each other, opposite charges attract each other
Light reflecting off the road, other cars, and water is highly polarized horizontally. Which diagram shows polarization of lenses that would be most useful as sunglasses when outdoors or driving? The white lines represent the direction of polarized light that will pass through the lens to your eye.
Lines straight vertical
Which unit is used to measure period?
Minutes
Is ink in your computer printer an example of mixing pigments or mixing light, and why?
Mixing pigments because the inks do not produce their own light
Why won't a chain reaction occur in natural uranium?
Most natural uranium is U-238, which will not go through fission easily
Who invented the reflecting telescope?
Newton
What would happen to a charged particle at rest in a magnetic field
Nothgin
To understand optical phenomena, what is one important thing to keep in mind?
Our brains always interpret light as if it always travels in straight lines
Which diagram shows light refracting in a convex lens
Oval shaped, light rays going through bend according to the shape of the lens
What substance would be a good insulator?
Paper
Which of the following statements is true?
Photons carry exactly the same energy that an electron was able to absorb
What is the common name of sound frequency?
Pitch
Which of the following is a practical application of concave mirrors?
Reflecting telescopes
Which phenomena are involved in the formation of mirages
Refraction
What is one primary reason rainbows form?
Refraction and reflection
Why are protons positive and electrons negative?
Scientists assigned those values based on observed behavior of protons and electrons
Which of the following best provides evidence that there is a nuclear strong force?
Scientists have seen that multiple protons that close together exert very strong electrical force. There must be a very strong force to hold them together
How does sonar (echolocation) work?
Sends out a sound wave, and wait for the echo. The time between when the sound wave was sent and the echo can be used to calculate distance in the equation d=vt.
Where does the mechanical energy needed to turn a turbine come from?
Steam, flowing water, blowing wind
What is the law of reflection?
The angle of incidence is equal to the angle of reflection
Describe the differences between absorption and emission spectrums.
The best responses include the ideas that absorption and emission spectrums are essentially the same thing. Absorption spectrums have the full rainbow spectrum with dark lines where energies are missing. Emission spectrums are black with just a few colors shining brightly. If the emission spectrum and the absorption spectrum for the same substance were combined, the bright lines of the one would coincide exactly with the dark lines of the other.
What is reflection?
The bouncing back of a wave from some barrier
How does an electric motor work?
The contacts are connected to a battery, so as current flows through the wire, the magnetic field it creates in the loop experiences a magnetic force to line with the stationary magnet's field. The loop turns as a result, and the momentum created carries it slightly beyond a true alignment, but by then the loop has switched the contacts, causing current to flow in the opposite direction. This again creates a magnetic field, which tries to line up with the stationary magnet's field, so the loop continues in the same direction. The process repeats, causing electric energy to be converted into motion. The current reverses direction at just the right moment to allow a fairly steady rotation.
What is a light year?
The distance light travels in one year
Which phrase describes a light year?
The distance light will travel in one year
Why do blue jeans appear blue?
The dye in the cloth reflects blue wavelengths
Which of the following best describes the image formed by a plane mirror
The image is virtual and the same size as the object
What is true for transverse waves?
The medium moves at right angles to the wave motion
What does the index of refraction represent?
The ration of the speed of light in a medium to the speed in a vacuum
What is dispersion?
The separating of waves into different frequencies by refraction in a medium
If a star is moving away from Earth at a high speed, which of the following would astronomers observe
The star's spectrum would be shifted towards red.
What keeps the protons in the nucleus of atoms from flying apart?
The strong force
What is meant by half-life?
The time for half of a radioactive sample to decay into new substances
What is a period?
The time it takes for one complete wavelength
How are radio waves different from visible light?
They differ only in frequency and wavelength
When ions form, what happens to the electrons?
They transfer to or from other nearby atoms
How can an atomic spectrum be used?
To identify elements and compounds
Which way will a light wave refract when it passes into a medium of greater induz of refraction?
Towards the normal line at the point where it passes from one medium to the other
How does the medium move in comparison to the actual wave?
Transverse: perpendicular, Longitudinal: parallel
A piece of iron can be made into a permanent magnet by stroking it with a strong magnet
True
An electromagnet can be made stronger by increasing the number of coils of wire
True
South poles are attracted to North poles
True
The angle of incidence is always equal to the angle of reflection
True; According to the law of reflection, the angle of incidence equals the angle of reflection. If a wave strikes a rough surface, and is diffused, we treat the angle of incidence at each microscopic point on the rough surface, and find that the law of reflection still holds true.
If light traveled at the same speed through air and water, then there would be no refraction as a ray of light went from air to water.
True; Recall that refraction is caused by a wave entering a new medium in which the wave speed would be different from the previous medium. IF light traveled at the same speed through air and water, there would be no change in speed, and hence, no refraction.
What does alpha radiation consist of?
Two protons and two neutrons ejected from the nucleus
How is the law of reflection used in the design of auditoriums
Using the law of reflection, the design of auditoriums incorporates the fact the sound waves reflect off of surfaces, and softer/irregular surfaces absorb sound. A balance of these two concepts is shown through the use of hard, smooth surfaces behind the band to reflect sound towards the audience, and soft, irregular surfaces used in the other three walls of the concert hall to absorb sound, without too much echo.
Which equation expresses Ohm's law
V=IxR
What unit is electromotive force measured in
Volts
Why do we see mirages?
Warm air bends light, but our brains see only straight lines
Which examples describe mechanical waves?
Water, vibrating guitar string, sound
What cause the sky to appear blue?
When a beam of light strikes an atom in the atmosphere, it causes the electrons to vibrate. The vibrating electrons re-emit the light in various directions, thus scattering the light. The atoms of our atmosphere are more effective at scattering blue light than other colors, so the sky appears blue.
What are some typical uses of convex mirrors?
Wide-angle mirrors, store security mirrors
what is a circuit
a complete path from high voltage to low voltage through which electric charge can flow
What is a lens?
a curved piece of glass that allows light rays to diverge or converge
What is a compression in a sound wave?
a place where the molecules of the medium are pressed closest together
Why does a green shirt appear green?
because it reflects green light
When you walk across the room and feel a shock as you touch the doorknob, you have experienced
charging by contact
a complete path for the flow of electrons is called a
circuit
a material that allows electrons to flow easily is called a
conductor
What are two ways that objects can become charged?
contact and induction
The three components of a nuclear reactor are
control rods, water, and nuclear fuel
An electric motor accomplishes what task?
converts electrical energy into mechanical energy
Which type of lens would correct the vision of a farsighted person?
convex
the unit used to measure electric charge is the
coulomb
green+blue=
cyan
When two waves overlap in the same medium, and the result is that the amplitudes cancel each other out, this phenomenon is called
destructive interference
Which of the following is involved in the formation of a rainbow?
dispersion and reflection
The electric force between two particles depends on which two characteristics?
distance and electric charge
which other forces are magnetic forces most like?
electric and gravitational
The volt is a unit used to measure
electric potential
An astronomer observes the light coming from a distant star. He notices several distinct bright lines in the spectrum. What kind of spectrum is he observing?
emission
Magnets will stick to any metallic surface
false
Which direction do electrons move in a circuit
from lower electric potential to higher electric potential
Which of the following has the most energy
gamma rays
Light reflected off of a horizontal surface is usually polarized
horizontally
What happens to the atomic number of an atom when an alpha particle is emitted?
it decreases by two
If the resistance doubles while the voltage stays the same, what happens to the current
it drops by one-half
blue+red=
magenta
If the eye is too long, and the image focuses in front of the retina, a person is
nearsighted
atoms which have more electrons than protons are said to have
negative charge
Carbon dating doesn't work on
non-organic objects
Which of the following characteristics of an object would allow no light to pass through
opaqueness
Where are electrons found in an atom?
orbital clouds
electric current describes the movement of what kind of charged particles?
positive and negative
Which particles are found in the nucleus of atoms?
protons and neutrons
Which particles can be found in the nucleus?
protons and neutrons
The visible spectrum is made of which of the following types of light?
red, orange, yellow, green, blue, violet
A "mirage" is caused by
refraction
A mirage is caused by
refraction
Which of the following explains why the sky appears red sometimes at sunset
scattering
What are the two main types of electrical circuits
series and parallel
what happens when a bar magnet is broken into two pieces?
still contains a north and a south pole
What is an angle of incidence
the angle that an incident line or ray makes with a perpendicular to the surface at the point of incidence
Which part of the eye controls the amount of light entering it?
the iris
Which statement best describes electric current?
the movement of charged particles in a conductor
What defines a chemical element?
the number of protons
What is the "atomic number" of an element
the number of protons
The "speed of light" (c) refers to the speed of all electromagnetic waves under what conditions
through a perfect vacuum
Sounds at frequencies above what we are capable of hearing are said to be
ultrasonic
Symbolic notation
upper: mass number lower: atomic number
What symbol is used to represent the wavelength?
upside down y
Which type of polarized sunglasses would help reduce glare the best?
vertically polarized
Which color of light is bent the most in a prism
violet
Electric power transmitted over large distances works best if it has high _______ and low _______
voltage; current
Ohm's law states that
voltage=resistance x current
blue+yellow=
white
green+magenta=
white
red + green + blue=
white
red+cyan=
white
red+green=
yellow
Which of the following colors of light are complementary when mixed together?
yellow and blue