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97 Cards in this Set
- Front
- Back
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Definition of a wave:
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a periodic series of disturbances
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Name 2 major types of waves:
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Electromagnetic and mechanical
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Name 2 types of MECHANICAL waves:
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Transverse and longitudinal
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What is a transverse wave?
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The medium moves perpendicular to the direction of propagation
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What is a longitudinal wave?
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The medium moves parallel to the direction of propagation
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What is a pulse?
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a singular disturbance
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Definition of amplitude:
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the maximum displacement from equilibrium position
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Definition of wavelength:
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the straight-line distance between 2 adjacent, in-phase points on a wave
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What does frequency depend on?
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the oscillator
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What does wave speed depend on?
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the medium
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Put the 3 phases of matter in order from fastest wave speed to slowest wave speed.
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solid, liquid, gas
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___________ waves do not need a medium.
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Electromagnetic
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What is the fundamental harmonic?
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the first harmonic
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The harmonics for one fixed end and one free end can only be ___ numbers
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odd
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The qualitative quality for frequency is:
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pitch
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The qualitative quality for amplitude is:
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energy (loudness)
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The qualitative quality for harmonics is:
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sound quality (timbre)
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What is resonance?
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One object causing another object to vibrate at its natural frequency.
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Is there a relationship between pulse speed and amplitude?
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No
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Is there a relationship between tension and pulse speed?
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Yes. More tension = faster pulse speed
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Is there a relationship between pulse speed and pulse width?
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No
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Is there a relationship between frequency and wavelength?
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Yes. Frequency and wavelength have an inverse relationship in the same medium.
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What is the Law of Reflection?
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The angle of incidence equals the angle of reflection (when measured from the normal).
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The direction of propagation is ______ to the wavefront.
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perpendicular
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What is a reflection?
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A reflection is a wave that bounces off a barrier that doesn't absorb the wave's energy.
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What changes occur to a wave that bounces off a straight barrier?
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Only direction
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What changes occur to a wave that bounces off a curved barrier?
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Direction and shape
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Define refraction:
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The bending of a wavefront due to a change in speed (generally due to a change in medium)
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What changes occur to a wave that enters a shallower region?
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Wavelength, wave speed, direction
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Define diffraction:
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The spreading of a wave beyond a small opening, without a change in speed
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In diffraction, the wider the opening...
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The smaller the angle by which the wave spreads out
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In order to get a more circular wave pattern as a result of diffraction, the width of the opening must be:
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closer to the width of the wavelength
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What is interference?
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When 2 or more waves travel through the same medium at the same time
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What are nodes (in interference)?
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areas of destructive interference
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What are antinodes (in interference)?
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areas of constructive interference
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Define the Doppler Effect:
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The apparent change in frequency due to the relative motion between the wave source and the observer
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Are electromagnetic waves transverse or longitudinal?
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Transverse
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Can EM waves travel at different speeds?
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No, they all travel at the speed of light.
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What are standing waves?
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When two identical waves travel through the same medium at the same time but in opposite directions
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Within a standing wave, regions of constructive interference are called _______ and regions of destructive interference are called _______
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Antinodes; nodes
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Along the same string for standing waves, all resonances have (same/different) speeds
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same
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What is the Law of Refraction?
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If a light ray enters a more optically dense medium, it bends toward the normal
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Addition of color is based on:
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light
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Subtraction of color is based on:
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pigments
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In convex lens, parallel light rays bend toward:
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the focus
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If a light ray enters a LESS optically dense medium, it bends (away from/toward) the normal.
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Away from
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In terms of angles, when does total internal reflection occur?
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When the angle of incidence is greater than the critical angle
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What about the medium must be changed in order for total internal reflection to occur?
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The light ray must be moving from a MORE dense medium to LESS dense medium.
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Define focal length:
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The distance between the lens plane and the focal point
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Concave lens; light (diverges/converges)?
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Diverges
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Convex lens; light (diverges/converges)?
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Converges
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If half of a lens is covered up, the image will be:
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dimmer
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What is a real image?
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An image that can be projected onto a screen. Light rays actually converge at a single point.
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What is a virtual image?
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Image cannot be projected onto a screen. The illusion seen by the eyes tricks us into thinking that light is converging.
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The smaller the index of refraction, the (faster/slower) light will travel through
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faster
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What is the Law of Charges?
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Like charges repel. Unlike charges attract.
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What is Conservation of Charge?
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Total charge you start with = Total charge you end with (can't lose e-)
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Electrical force is generally (greater/smaller) than gravitational force?
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greater
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Define electric field:
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The region surrounding a charged particle where another charged particle experiences either a force of attraction or repulsion
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Electric fields are (uniform/inverse square)
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Inverse square (gets weaker with increasing distance)
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Electric field lines move from ______ to ______
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Positive to negative
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Can electric field lines cross?
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No
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Electric field lines are always (perpendicular/parallel) to the surface of an object
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Perpendicular
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Charge is separated by (induction/conduction)
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Induction
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Charge is transferred by (induction/conduction)
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Conduction
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What kind of charge (negative/positive) always moves?
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Negative only
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Define electrical potential energy:
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The potential energy associated with an object due to its position relative to a source of electric force
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What are lines of equipotential?
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Lines that connect points of the same potential; always perpendicular to electric field lines
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What is the relationship (equation) among voltage, power, and current?
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P = IV
power = current x voltage |
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The units of a watt can be:
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J/s or C/s
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When batteries are connected in series, the potential difference (increases/decreases/stays the same)
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Increases
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When batteries are connected in parallel, the potential difference (increases/decreases/stays the same)
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Stays the same
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Voltmeters are wired in (series/parallel)
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Parallel
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Ammeters are wired in (series/parallel)
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Series
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Define power:
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The rate at which energy is provided or consumed
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Voltmeters measure:
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Potential difference across a resistance
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Define magnetic field:
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A region of space in which a MOVING charged particle experiences a magnetic force
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Define Law of Poles:
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Opposite poles attract. Like poles repel.
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Magnetic field lines run ______ to ______ on the EXTERIOR of a magnet
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North to south
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Magnetic field lines run ______ to ______ on the INTERIOR of a magnet
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South to north
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Can magnetic field lines form a partial loop?
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No. They only form complete, closed loops.
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Can magnetic field lines cross?
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No
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The earth's magnetic south pole is near the geographic _____ pole.
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North
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What are magnetic domains?
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Microscopic magnetic regions composed of a group of atoms whose magnetic fields are aligned in a common direction
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In order for a magnetic field to exert a force on a charged particle, TWO conditions must be met:
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1. The charge is moving
2. The charge cannot be moving parallel to the direction of magnetic field lines |
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What is the unit of magnetic field?
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Tesla (T)
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Tesla can be converted to other units. Give 3 examples.
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1. N/(C*m/s)
2. N/(A*m) 3. (V*s)/(m^2) |
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Equation for force on a charged particle in a magnetic field:
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F = qvB
force = charge x velocity x magnetic field strength |
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Equation for force on a current-carrying wire in a magnetic field:
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F = BIl
force = magnetic field strength x current x length |
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Parallel currents going in the same direction makes 2 wires (attract/repel)
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Attract
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Currents going in opposite directions make 2 wires (attract/repel)
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Repel
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What does a motor do?
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Converts electrical energy into mechanical energy
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What does a SPLIT-ring commutator do?
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Maintains unidirectional current flow
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What does a SLIP-ring commutator do?
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Maintains bidirectional current flow
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What does a generator do?
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Converts mechanical energy into electrical energy
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A step-up transformer (increases/decreases) voltage.
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Increases
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A step-down transformer (increases/decreases) voltage.
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Decreases
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