Physics Final 2
Terms
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- electromagnetic waves are what types of waves?
- transverse
- electromagnetic waves can/can't travel through a vacuum.
- can
- WHich visble light wave had the shortest wavelength?
- violet (ROY G BIV goes longest to shortest)
- compared to the wavelength of a ultraviolet waves, the wavelength of infrared waves is____________.
- longer
- Compared to the velocity of radio waves, the wavelength of infrared waves is _____________________ and ________________.
-
-same in a vacuum
-slower in a medium - the source of all electromagnetic waves is___________.
- vibrating electric particles
- The main difference between a radio wave and a sound wave is its_______________.
- basic nature of the waves
- radio waves travel at the speed of light, 300,000. The wavelength of a radiowave recieved at 100MHz is _______.
- 3 meters
- sound waves in the air are a series of _____ or __________.
- compressions or longitidunial waves
- the speed of a sound wave depends on what?
- temperature
- When the handle of a tuning fork is held solidly against a table, the sound becomes louder and the length of the fork vibrates ______________
- become shorter
- the phenomenon of beats results from _________________.
- wave interface
- What is the time needed for a wave to make one complete cycle?
- period
- Beats are produced when two tuning forks, one of 240Hz and the other of frequency 246Hz are sounded together. The frequency of beats is what?
- 6Hz
- The distance between the sucessive identical parts of a wave is called its what?
- wavelength
- What is hertz a unit of?
- frequency
- What type of wave is created when shaking a rope up and down?
- transverse wave
- What is it called when two or more waves are at the same place at the same time?
- interference
- Where can you touch a standing wave on a rope without disturbing the wave?
- node
- What is the doppler effect?
- the change in observed frequency due to the movement by the observer or the source of sound
- When a sound source moves towards you, what happens to the wave?
- it stays the same
- Some of a wave's energy is always being dissipated as heat. In time this will reduce the wave's _______________.
- amplitude
- If the amplitude of a particular wave is 1 meter, what is the top-to-bottom distance of the disturbace?
- 2 meter
- If you double the frequency of a vibrating object, what will its period do?
- decrease
- You dip your finger repeatedly into water and make waves. If you dip your finger into more frequently, the wavelength of the wave does what?
- decreases
- A child swings on back and forth on a swing. If the child stands rather than sits, the time for the swing to go back and forth_______________.
- decreases
- What happens when an airplane is flying faster than the speed of sound?
- sonic boom occurs
- When observer on the ground hears a sonic boom, how fast is a plane going?
- faster than the speed of sound
- When does the doppler effect occur?
- when a source of sound moves towards an observer
- What is the frequency of the second hand on a clock?
- 1/60 of a second
- Two wavelngths arrive at the same place at the same time exactly in step with each other. Each wave has an amplitude of 1 meter. The resulting wave will have an amplitude of what?
- 2 meters
- A certain ocean wave has a frequency of 0.05Hz and a wavelength of 10 meters. What is the wave's speed?
- 5m/s
- THe period of an ocean wave is 10 seconds. What is the wave's frequency?
- 1/10Hz
- A weight on the end of a spring bobs up and down one complete cycle every 2 seconds. Its period is ______.
- 1/2Hz
- A weight on the end of the a spring bobs up and down one complete cycle every 2 seconds. WHat is its period?
- 1/2 second
- How long does it take the sun to reach the earth?
- 8 minutes
- A leaf on a pond oscillates up and down two complete cycles each second as a water wave passes. What is the speed's frequency?
- 2Hz
- What do heat lamps usually give off?
- infrared
- When in the water the speed of light is faster/slower than when in the air
- slower
- Glass is transparent to visible light but not to ________________________.
- loose electrons
- What has to do with shiny surfaces of metals?
- loose electrons
- Do clouds block UV light?
- no
- What color travels fastest through clear glass?
- red
- If a shadow is produced by an object held close to a peice of paper in the sunlight, how will the image on the peice of paper show up?
- sharp
- What is the ultimate source of electromagnetic waves?
- vibrating charges
- If a photographer wishes to use a safety light in the dark room that will emit low-energy photons, what is the best color of light for him to use?
- red-the lowest energy
- What color light carries the most energy?
- violet
- How fast is a light second?
- 300,000km
- After randomly polarized light passes through a polarizer, it is __________
- polarized?
- If two polarized filters are held with their polarization axes at right angles to each other, the amount of light transmitted compared to when their axes are parallel is________.
- 0
- Sunlight contains all colors but it mainly contains what color?
- yellow
- The earth recieves a lot of ultraviolet radiation from the sun. Luckily most of it doesn't reach the ground beacause it is__________________________.
- blocked by the ozone layer
- Light shines on a pane of green glass and a pane of clear glass. The temperature will be higher in what pane of glass?
- green glass
- Color is seen on tv thanks to what?
- color addition
- A tennis ball is more easily seen if it is what color?
- yellow-green
- Different colors of light correpond to different_________________.
- light frequencies
- What are complimentary colors?
- two colors that produce white light
- When yellow and blue are mixed together to create green, what colors are absorbed?
- all except green
- The simularity/difference between Columb's law and Newton's law of gravity
-
similarity- both vary inversely to the square of the proportion
difference- gravity only attracts while the other attracts and repels - What is the difference between an insulator and a conductor? Which is copper? Wood? Distilled water?
- an insulator doesn't allow the flow of electricity while a conductor does and creates electricty
- What are three ways an object can become charged? explain each.
-
friction-rubbing 2 objects together
contact- a charged object coming in contact w/an insulator that has tightly bound electrons
induction- a charged object coming close but not touching another charged object - WHy should you not sit or stand in water when using electrical appliances?
- b/c water is a good conductor
- Columbs law says there are two kinds of charges. What are they?
- positive and negative
- A material is a good insulator if?
- it has tightly bound electrons
- A material is a good conductor if?
- it has tightly bound electrons
- Semiconductors are good conductors and insulators. Explain.
- they are good conductors until they are induced to change state
- Atomic nuclei almost always consists of what?
- protons and neutrons
- What do two like charges do?
- repel
- What do protons and electrons do?
- attract
- Electrical forces between charges are normally strongest when the charges are close/far apart?
- close
- Columb's law says that the force between any two objects depends on what?
- amount of charge and the distance between the charges
- WHen the distance between two charges is halved the electrical force between the charges is what?
- quadroupled
- A positive ion has what?
- more protons than electrons
- If you comb your hair and the comb becomes positively charged, your hair becomes _______________.
- negatively charged
- Charge carriers in a metal are electrons rather than protons because electrons are ______________.
- negative
- Bring a charged object near a conductor and then momentarily touch the conductor. This demonstrates charge by______________.
- contact
- Two charged particles held close to each other are released. As they move, the acceleration decreases. Therefore, the particles have what kind of charges?
- like charges
- What is an electric field?
- a force field that fills the space around every charge or group of charges
- What are field lines and how are they represented?
- force per charge.... vectors
- A mass of protons has what two types of fields around them?
- gravity and electric
- A positive test charge in a field determines what properties of the field?
- magnitude and direction
-
A large positive charge is transferred to a large metal sphere, what is the field strength:
a. outside the sphere
b. inside the sphere -
a. very large
b. zero - What is the field strength inside a sphere and why is it that value?
- zero b/c the charges are evenly distributed
- What is electric potential energy determined by?
- the charge's location
-
identify whether the potiental energy increases or decreases for the following:
a. a positive charge moved closer to a negative charge
b. a positive charge moved closer to a positive charge
c. a negative charge moved clos -
a. decreases
b. increases
c. increases
d. decreases
e. increases
f. increases
g. decreases
h. increases - what is a volt?
- a unit of electric voltage
- What is an ampere?
- a unit of electric current
- What is a Van de Graff generator?
- a machine that generates large electric voltages
- A beam of electrons accelerate from the back of your tv set to the screen. In order to make the beam hit the bottom of the screen, oppositely charged parallel plates create a vertical electric field. How will the top plate be charged?
- negatively
- Two parallel plates are oppositely charged. The left plate is negative and the right plate is positive. In which direction does the electric field point?
- positive towards negative
- Electric field lines between two oppositely charged parallel metal plates will be _______________ and _____________.
- parallel and have an equal distance
- The electric field inside an uncharged metal ball is zero. If the ball is negatively charged, the electric field inside the ball must be ______?
- zero
- What is required in order for there to be a flow of charge from one place to another?
- ther must be a conductor and an electric potential difference
- In solid conductors, electric current of flow is___________
- electrons
- an ampere is a measurement of what?
- current
- Electric resistance in a wire depends on a wire's ______________ (3 things)
-
-conductivity
-temperature
-thickness - Compared to thin wires, electric resistance in thick wires is __________.
- less
- For most conductors, as their temperature increases, their resistance____________.
- increases
- A man experiences electric shock. Where do the electrons making the shock come from?
- the man himself
- A wire carrying current is normally charged ____________.
- not at all
- Current from a battery is always what?
- direct current
- Where do electrons come form that produce heat and light in a filamentof the light bulb?
- the filament
- If you plug a hair dryer rated at 110V into a 220V outlet, the current in the hari dryer will be__________.
- doubled
- Electric power is ________ times ________.
- voltage times current
- The current through a 12 ohm resistor connected to a 220V power supply is______
- 10 amps
- A 1000 ohm resistor has a 5 amp current in it. What is the voltage across the resistor?
- 30 amps
- What is the resistance of a toaster that uses 4 amps when connected to a 120V power source?
- 30 ohms
- How much power is used by 12.0V flashlight battery that draws .25A of current?
- 3 watts
- When plugged into a 120V wall outlet, how much current used by a toaster rated at 2400W?
- 20 A
- A 100W light bulb is connected to a 120V outlet. How much current exsists in the light bulb?
- .83A
- A power line with a resisatnce of 2 ohm has a current of 100A in it. The power dissipated in the line is _________
- 20000 watts
- What does the law of reflection state?
- that the angle of reflection is equal to the angle of incidence
- What is known about the virtual image created in a mirror
-
-reflected rays diverge
-image behind mirror
-image upright - When a light beam emerges from water into air the average light speed _______.
- increases
- What mostly has to do with a mirage?
- diffraction
- Different colors trael at different speeds in a transparent medium. In a vacuum, different colors of light travel at ____________.
- the same speed
- The spectrum produced by a prism or a rain drop is evidence that the average speed of light in a material depends on the light's _______.
- color
- If you walk towards a mirror at a certain speed, the relative speed between you and your image is what?
- quadroupled
- What is the shortest a plane mirror can be to see your whole image?
- 1/2 your height
- What does a beam of light travel fastest in?
- a vacuum or the least dense material
- In a curved optical fiber, light travels ____________
- internally reflects in a sucession of straight line paths
- What is the rainbow an example of?
- diffraction
- A converging lens ___________________.
- bends parallel rays at single points
- An image of a distant object formed by a single converging lens is....
-
-real
-upside down
-can be focused on a machine
-can be projected on a wall - What is a magnifying glass?
- a converging lens
- The reason the bottom lines of a swimming pool can look wavy when seen from above is beacuse _________________.
- the uneven water surface is refracting at different angles
- If an object is located at a focal length of the diverging lens, then compared to the object, the image will appear _________.
- smaller
- If an object is located inside the focal lens, the image will appear to be ___________.
- right side up
- All lenses rely on having a ____________.
- slower speed in the lens
- WHich instrument is the human eye most similar to?
- camera
- A simple astronomical telescope consists of a pair of ______ lenses.
- converging
- When slides are put right side up into a slide projector, the images are _____________.
- upside down
- If light traveled at the same speed in glass as it does air, images would look ______________.
- the same w/o a telescope
- The image your eye recieves is _______.
- upside down
- on a bright day, the iris of the eye changes so the pupil ________.
- becomes smaller
- All magnifying glasses under water will _____________.
- magnify less
- The wavy bright and dark lines at the bottom of the pool are a resultof the water surface acting like moving _________.
- lenses
- Suppose you are 2 meters in fornt of a plane mirror and you want to take your picture. From what distance should you take the picture?
- 4 meters
- Huygens' priciple says that _______________.
- each point on awave acts as a new wavelet
- As you get farther and farther away from a point source of waves the wave fronts appear ___________.
- flatter
- When a plane wave passes through a n opening, the wave fronts will not change much if the opening is _________.
- large compared to the wavelength
- When a wave passes through an opening some of the wave is bent. What is this called?
- diffraction
- Diffraction occurs for what types of waves?
- all
- What is diffraction the result of?
- interference
- Colors seen when gasoline forms a thin film on water are a demonstration of what?
- destructive interface
- When do wave diffract the most?
- when their wavelengths are long
- Constructive interface occurs when __________.
- the crests OR troug
- Destructive interface occurs when_________.
- crests AND troughs overlap
- When monochromatic light shines through two closely spaced narrow slits and onto a screen some distance away, the pattern on the screen has ____________.
- alternates of light and dark
- A diffraction grating consists mostly of _________.
- many closely spaced narrow slits
- What is it called when gasoline drips onto a wet street and you can see a beautiful spectrum of colors?
- irridescence
- A thin film appears blue when illuminatedwith white light. The color being canceled by destructive interface is _______.
- all colors except blue
- What is coherent light?
- many different rays of light all having the same phase, frequency, wavelength, and direction
- What is light emitted by a laser?
- coherent
- A hologram is most closely related to a _________.
- diffraction grating
- Monochromatic light refers to light that is what?
- of only one color