Physics 2nd Semester Exam
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- What is a rythmic disturbance that carries energy through matter or space?
- Wave
- What is a single disturbance traveling through a medium?
- Wave pulse
- What are the two main types of waves?
- Electromagnetic and mechanical
- What type of waves do not need a medium to travel through?
- Electromagnetic
- What type of waves require a source of energy and an elastic medium?
- Mechanical
- 2 main kinds of mechanical waves
- Transverse and longitudinal
- type of mechanical waves causes particles to vibrate perpendicular to the direction of the wave
- Transverse
- type of mechanical waves causes particles to vibrate parallel to the direction of the wave
- Longitudinal
- position (displacement) and motion (velocity) of a point on a wave
- Phase
- Points on a wave are 180 degrees out of phase if...
- They have equal and opposite displacements and velocities
- linear distance between any point on the wave and the next closest point that's in phase with it
- Wavelength
- number of wavelengths/pulses that pass a given point each second
- Frequency
- time required for one wavelength/pulse to pass a given point
- Period
- SI unit of frequency
- Hertz
- linear distance traveled by the wave per unit of time
- speed
- EQUATION: V=
-
(lambda) f
-------- OR -------
T (lambda) - max displacement of vibration particles from their equilibrium position
- Amplitude
- loss of energy (amplitude) due to friction
- damping
-
Speed of Waves
1)doesn't depend on..
2)doesn't depend on..
3)depends on.. -
1)energy being transmitted
2)amplitude of wave
3)nature of wave and the medium - waves propogate in a straight line perpendicular to the wave front
- rectilinear propogation
- EQUATION: Law of reflection
- angle i = angle r
- bending of a wave around edge of a barrier
- diffraction
- points of zero displacement
- nodes
- points of max displacement
- loops
- sound waves are these types of mechanical waves
- longitudinal
- speed of sound in air at room temp.
- 343 m/s
- amplitude of sound as measured on a log scale
- sound level
- sound level is measured in..
- decibels
- loudness of sound depends on 2 things..
- amplitude and frequency
- ___ dB increase is perceived as a doubling of the loudness
- 10
- most people can't hear below ___ Hz or above ___ Hz
- 20-16,000
- people are most sensitive to sounds between ___ & ___ Hz
- 1,000-5,000
- frequency of a sound wave
- pitch
- change in pitch due to relative motion between sound source and the ear
- dopplar shift
- created by constructive interference; high pressure wall that an object has to pass through to go faster than speed of sound
- sound barrier
- spy plane; flies 5 mi higher than other aircraft; fastest aircraft; almost invisible to radar
- blackbird
- fighter/bomber plane; often invisible to radar
- nighthawk/stealth fighter
- vibrating sound source is placed in contact with a larger object and forces it to vibrate
- forced vibrations
- a force is applied to an object everytime it undergoes a complete vibration
- resonance
- easiest frequency to produce in an object
- natural frequency
- a closed-pipe or open-pipe resonator resonates at ____ intervals
- 1/2 lambda
-
EQUATION:
L(b) - L(a) = - 1/2 lambda
- sound produced by an object vibrating only at its natural frequency
- pure tone
- tones which come from vibrations having a frequency greater than the fundamental frequency
- over tones
- depends on the number of overtones produced; richness
- quality/timbre
- refers to the number of overtones present plus their intensity
- harmonic content
-
general string EQUATION:
k= -
f x l x d x '/D
---------------
'/F - interference effect from the superposition of 2 waves of slightly different frequency
- beat
- # of beats per sec =
- difference between frequency of component waves
- human ear can recognize up to ____ beats per sec
- 10
- 3 properties of light known during the 17th century
-
1)regular reflection
2)refraction
3)rectilinear propogation - this theory said light consists of very small particles moving at a very fast speed; advocated by Newton
- Particle Theory
- this theory said light was a wave; advocated by Huygens
- Wave Theory
- advocated the wave theory
- Huygens
- advocated the particle theory
- Newton
- this man discovered light travels slower in water than air
- Foucault
- developed the electromagnetic theory
- James Clerk Maxwell
- confirmed the electromagnetic theory experiementally
- Hertz
- radiation just before red; gives sensation of warmth; causes atoms and molecules to move
- infrared radiation
- radiation just beyond violet; 3 different types
- ultraviolet radiation
- discovered x-rays
- Roentgen
- discovered radioactivity
- Becquerel
- discovered the electron
- Thomson
- 3 radioactive elements.. 2 were discovered by the Curies
- thorium, polonium, radium
- 3 types of radiation
- alpha, beta, gamma
- date of the birth of modern physics
- 1900
- this hypothesis said vibrating particles in the hot objects studied only emit packets of energy
- Planck's Quantum Hypothesis
- packets of energy
- quanta/photons
-
EQUATION: Planck's Quantum Hypothesis
E= - h x f
- the emmission of electrons by a substance when illuminated by electromagnetic radiation
- photoelectric effect
- man who published the first quantitative studies of the photoelectric effect
- Lenard
- says light is made up of quanta/photons; explained the photoelectric effect
- Einstein's Quantum Theory of Light
- atomic spectra were first discovered by these 2 men
- Kirchoff and Bunsen
- order of the models of the atom
- Dalton's indestructable; Thomson's plum pudding; Rutherford's nuclear; Bohr's planetary
- discovered electric arc lamp
- Davy
- invented the first practical bulb
- Edison
- most efficient light
- Fluorescent
- science of how light interacts with life
- photobiology
- proposed that matter has wave properties
- de Broglie
-
EQUATION:
wavelength of matter = -
h
---------
m x v - these two men confirmed de Broglie's prediction of the wavelength of matter
- Davison & Germer
- light with the same frequency
- monochromatic
- LASER =
- Light Amplification by Stimulated Emission Radiation
- first person to make a careful study of color
- Newton
- band of colors
- solar spectrum
- light consisting of many colors
- polychromatic
- 2 properties of glass
- transparent & dispersive
- this spectrum is produced by incandescent solids, liquids, or gases under high pressure
- continuous
- this spectrum is produced by exciting a low density gas with heat or electricity
- bright-line
- this spectrum is produced by passing white light through a cool gas
- dark-line spectrum
- man who discovered the dark lines in the solar spectrum
- Fraunhofer
- if a star has a high frequency shift, it's moving
- toward us
- if a star has a low frequency shift, it's moving
- away from us
-
complementary colors..
1)Red
2)Green
3)Blue -
1)Cyan
2)Magenta
3)Yellow - 3 primary colors of light
- red, green, blue
- 3 primary pigments
- magenta, yellow, cyan
- you can see a rainbow when..
-
1)the sun is behind you
2)angle formed is 40-42 - light that only vibrates in one plane
- polarized light
- emission of light during the absorption of radiation
- fluorescence
- emission of light after the light sorce has been removed
- phosphorescence
-
EQUATION: law of refration (snell's law)
n = -
sin i V(air)
n = ----- = -----
sin r V(material) - branch of electronics that deals with static electricity
- electrostatics
- matter through which an electron can easily pass
- conductor
- matter through which electons can't easily pass through
- insulator
-
EQUATION:
F = -
Q1 x Q2
K x -------
d^2 - described by lines of flux
- magnetic field
- described by lines of force
- electric field
-
EQUATION: Electric Field Intensity
E= - F/q
- rate of flow of charge through a conductor
- electric current
- SI unit of electric current
- ampere (A)
- opposition electrons encounter as they pass through conductor
- electric resistance
- SI unit of resistance
- ohm
- conducting loop of wire through which a current can transfer electric energy from a suitable source to a useful load
- electric circuit
- safety current must go through
- fuse
- magnetic switched which open when circuit is overloaded
- circuit breakers
- tells you how much energy electrons have coming from a power source
- voltage
-
EQUATION: Ohm's Law
V = - I x R
- rate at which electrical energy is used
- electrical power
-
EQUATION:
P = - I x V
- more devoid of matter than the best vacuum on earth
- interstellar space
- a nebula turns into a
- globule
- a globule turns into either a
- planet or star
- a red giant turns into a
- white dwarf
- a white dwarf turns into one of 3 things..
- black dwarf, nova, supernova type I
- emits pulses of electromagnetic radiation; neutron star
- pulsar
- first person to do calculations that explained a black hole
- Oppenheimer
- consumes stars and releases tremendous amounts of energy when its first formed
- quasar