Normal Size Small Size show me how
9th grade Physics
|Through what mediums can mechanical waves travel?
|solids, liquids and gases.
|How are mechanical waves created?
|a source of energy causes a vibration to travel through a medium
|what direction does a transverse wave travel?
|travels perpendicular- crest and troughs
|what direction does a longitudinal wave travel?
|parallel compressions and rarefractions
|What direction does a surface wave travel?
|both parallel and perpendicular
|When a surfer rides an ocean wave on her surfboard, she is actually riding on a what?
|What is the period of a wave?
|the time it takes for a wave to complete one cycle?
|what are the two formulas for the speed of a wave?
|wavelength x frequency wavelength/ period
|how do you measure the amplitude of a transverse wave?
|from is rest position to a crest or trough.
|how are amplitude and energy related?
|the more energy a wave has the greater the amplitude.
|what is the term that describes when a wave strikes a barrier and bounces back?
|How is reflection different from refraction and diffraction?
|reflection does not change the wavelength, amplitude or frequency
|does the angle light strikes a new medium affect refraction?
|what causes the most diffraction?
|if the wavelength is too large compared to the opening or obstacle?
|What is the difference between constructive and destructive inference?
|constructive: creates a larger displacement destructive: creates a wave with a smaller displacement.
|how is a standing wave formed?
|only if half its wavelength or a multiple half fits exactly into the length of a vibrating cord.
|what type of wave are sound waves?
|which medium does sound travel the fastest in?
|how does a sonar work?
|the distance is calculated using the speed of sound in water and the time that the sound waves takes to reach and the objects take to return.
|what is resonance and what does it do to sound?
|resonacnce is the response of two sound waves of the same frenquncey. is use to create dramatic sound.
|what is the Doppler effect?
|as the distance from a sound source increases, the intensity increases.
|which part of the ear amplifies sound?
|the middle ear.
|how do electromagnetic waves vary?
|how they're produced and how they travel.
|how do you calculate frequency of an electromagnetic wave?
|speed/ wavelength. speed = 3.00 x10^8
|how does light behave as a wave?
|has constructive and destructive interference.
|how does light behave as a particle?
|uses photons- packets of electrons.
|What color has more photons red or blue
|What happens to intensity as you move away from a light source?
|what is the full range of frequencies of electromagnetic radiation called
|name the electromagnetic spectrum in order of increasing frequencies.
|radio waves, microwaves, infrared radiation, visible light, uv ray, x rays gamma rays.
|cell phones use what type of wave?
|how do bones look on xrays
|how does soft tissue look like on x rays
|how does light interact with transparent material
|it is transmitted
|how does light interact with translucent material
|it is scattered
|how does light interact with opaque?
|it is absorbed or reflected
|what occurs when light wave bends when its goes through another medium?
|reflected, absorbed or transmitted
|what is dispersion of light?
|the process of white light separating into color.
|how can dispersion happen in the atmosphere?
|raindrops, the drops act like a prism so when the light enters it slows down and refracts.
|what determines the color of an object?
|what is it made of and the color of light that strikes it.
|why do blue and yellow combine to produce white light?
|because the are complementary colors of light?
|what are the primary colors of pigments, and what do the produce
|cyan, magenta, and yellow- produce any other color
|what are the primary colors of light
|green, red and blue- create all possible colors
|what happens if a atom gains or looses and electron
|a net electric charge.
|what determines the strength of an electric field?
|the amount of charge the distance from the charge
|what are the three ways a charge can be transferred?
|contact- Graff sphere, induction placing your hand around a doorknob but no contact- and friction- rubbing your hair on a balloon.
|what type of curren is produced by a battery?
|what is the difference between a parallel and series circuit?
|parallel; can still operate if one element stops series: cannot function if one element stops
|what is a conductor?
|a material that makes charge easier to flow.- metal/copper
|what is a insulator?
|a material that does not conduct charge well- rubber and wood
|what affects the resistance of an object
|thickness, temperature and lenght
|what would produce the lowest resistance
|a thick, cool and short wire
|a thick, hot, long would produce what
|lots of resistance.
|what is the difference in electrical potential energy between two places in an electric filed is known as?
|potential difference/ voltage
|what is maintained across the terminals of a battery
|a voltage drop.
|what is ohms law
|v= r x i
|what is the unit for electric power
|what is the unit of electrical energy ?
|what is the equation of electric power
|E= current x voltage
|what is the current for electrical energy
|ee= power x time
|what are 5 examples of electrical safety?
|correct wiring, grounding, fuses, circuit breaker and three prong plug.
|how does a gfcl work
|it monitors currents flowing and from an outer appliance
|what is a analong signal?
|produced by a changing voltage and current
|what is a digital signal?
|encodes information as a string of 1's and 0's
|what is a vacuum tube used for?
|strength signals change alternating currents into direct currents turning currents on and off..
|what is a semiconductor?
|a solid that only conducts under certain conditions
|what is a cathodes-ray tube
|it controls the strength and position of the beams to produce images.