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| __ is proportional to the number of field lines passing through a surface |
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| South magnetic pole is at the geographical N/S pole |
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| General motion in B. Perpendicular v causes ___, parallel v causes ___. Combined, they cause ____. |
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| circling, nothing, spiraling |
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| Net F in a current carrying coil is? |
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| to get torque from a loop |
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| superposition lots of tiny rectangles. find torque in each one and add them |
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| For torque at a moment, when does equilibrium occur? |
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| according to ampere's law, how do you calculate an uneven path? |
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| Forces between parallel currents. Parallel I's attract or repel? |
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| Longer wire = less/more force |
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| Moving a wire in a magnetic field generates? |
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| ___ can be described as B cutting through an area (A) |
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| ____ is a law that describes a magnetic field trying to oppose u (dipole moment)... or that an induced u opposes flux |
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| Increased number of turns in a coil increases/decreases EMF |
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| AC/DC generators keep switching polarity |
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| flux is always in the same direction of/opposes the direction of B field |
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| ____ law describes motion or change in B |
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| The flying ring demo demonstrated |
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| In an alternator or generator, what two variables are constant? |
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| Larger A = larger/smaller EMF |
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| ___ is when the EMF generated in one coil induces I in another coil |
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| ___ is when changing I in a coil also changes flux and therefore EMF |
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| In a single coil, internal flux is proportional to ____. |
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Definition
| current (self inductance) |
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| Compare the inductance of two solenoids, which are identical except that solenoid 2 has twice as many turns as solenoid 1. |
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Definition
| L2=4L1 ... because increasing N also increases flux = double effect on L |
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| In a decaying current, coil energy is dissipated in __ |
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| A generator is a(n) A/C or D/C source |
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| Where is energy stored in a solenoid? |
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| How are coils and capacitors different from resisors? |
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Definition
| they don't store E and the don't have phase shift |
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| Capacitors speed up/slow down current |
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| current peak comes before voltage peak -- current leads, voltage lags |
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| Voltage can be describe by a change in ___ |
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| current... no change in current = no V |
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Definition
| voltage leads, current lags |
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Term
| In an inductor, reactance increases/decreases with a higher f |
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| To increase frequency of resonance, you need to increase/decrease capacitance. |
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| When an AC circuit is being driven at it's resonant frequency, how do Vc and Vl compare? |
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| A coil with I acts as a ____ and generates ___. |
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| In transformers, increasing the current in the primary increases ___ through primary and secondary |
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Term
| electromagnetic fields involve an electric and a magnetic field that are parallel/perpendicular to each other |
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| ____ light "bounces" off a surface |
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| ___ light travels through the material |
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Which gives the largest average energy density at the distance specified? and what does this mean?
a. 50W source at distance R
b. 100W source at distance 2R
c. 200W source at distance 4R |
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| ___ can generate E field or detect it, depending which direction the field is going |
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| ___ antenna generates B field |
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| Which is more important as far as intensity goes? R or P |
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| If the E field of an EM field is doubled, the energy density is ? |
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| Absorption in an oscillating EM field is only achieved when? |
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| When energy is absorbed, what direction is impulse? |
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| ____ is the plane in which E field is aligned... provides net direction |
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| A polarizer does what to light? |
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Definition
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| A ray of light is transmitted through two polarizers that are perpendicular to each other. How much light gets through? If a third polarizer at 45deg to the first two is inserted between them, does any light get through? What does this prove? What would happen if we were to insert an optically active material instead? |
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Definition
| none, yes, cancelled light can reappear, more light would get through |
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Term
| Optically active materials that can rotate light are comparable to? What component of the materials determines how much they will rotate light? |
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Definition
| multiple polarizers, length |
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Term
| In solids that rotate polarization, very little __ is lost. |
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Definition
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Term
| Polarization and reflection: Brewster's angle |
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Definition
| When the angle between the refracted ray and the reflected ray is 90deg, the reflected beam is 100% polarized |
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Term
| Sounds moves with respect to ___. |
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Definition
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| ___ spectra are produced by thin gasses. Lines correspond to photons emitted when excited atomic states in the gas make transitions back to lower-lying levels. |
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| ___ spectrum: solids, liquids or dense gases emit light at all wavelength when heated. |
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| ___ spectrum occurs when light passes through a col, dilute gase. atoms in the gas absorb at characteristic frequencies. re-emitted light is unlikely to be emitted in the same direction --> dark lines in the spectrum. |
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Definition
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Term
| For the doppler effect for light, v is pos/neg if you are moving toward the object |
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Definition
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Term
| If you aim a doppler radar at an object moving toward you, the return beam is blue/red shifted |
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Definition
| blue -- blue shift returns to a higher frequency, red shift returns to a lower frequency |
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Term
| Total internal reflection |
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Definition
| why a diamond looks so sparkly -- when theta=sin-1(n1/n2), theta2=90deg ... light is completely reflected so that more rays go directly back to observer |
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Term
| Prism effect on refraction |
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Definition
| double effect of refraction |
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| The spreading of light into it's component colors is called |
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Definition
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Term
| In a prism, which light gets deflected more? red or blue |
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Definition
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Definition
| when a thin lens blurs the image instead of focusing it |
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Term
| ___ occurs when rays far away from the principle axis do not focus at the same point as those rays close to the principle axis |
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Definition
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| ___ occurs when different wavelengths of light focus at different points because different colors experience different indices of refraction when passing through the lens |
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Definition
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Term
| Fixing chromatic abberation |
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Definition
| use different lenses with different indexes of refraction |
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| Process by which the eye focuses by relaxing or contracting the lens |
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Definition
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Term
| Total phase shift comes from both ___ effects and ____ effects |
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Definition
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Term
| If you hold a small hand mirror close to you and then move it away, do you see more, less, or the same amount |
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Definition
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Term
| An ammeter measures ___, so if a wire is connected to an ammeter and surrounding a solenoid, and there is increasing current in the solenoid, what will the ammeter reading be? |
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Definition
| current, positive -- because increasing current = pos reading |
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Term
| The image created by a standard slide projector is real/virtual, smaller/larger |
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Definition
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Term
| The image created by a camera is real/inverted, smaller/larger |
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Definition
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| The image created by a magnifying glass is real/inverted, smaller/larger |
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Definition
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Term
| When light is reflected from the interface between two transparent surfaces, its phase shifts by 180 degrees only when? |
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Definition
| when the material on the incident side has a smaller n than that on the other side |
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