ac review Wednesday test

true

in series rl circuit frequency goes up with xl, vl, zt, theta true or false

true

inductance values goes up so it is directly proportional to inductive reactance? true or false

true

is XL proportional to frequency? true or false

lenz law

when the current through a coil changes and an induced voltage is created as a result of the changing magnetic field, the direction of the induced voltage is such that it always opposes the change in current? which law is this? faradays law, lenz law, murphys law, law of returns

quadruples

when the current through an inductor doubles the stored energy doubles, quadruples, is halved, does not change

decreases

when the resistor voltage in a series rl circuit becomes greater than the inductor voltage the phase angle - increase, decrease doubled, not a factor

a

which values stays the same in parallel rl circuit when frequency increases? a. IR1 and voltages across components b. xl and IL1 c. voltages and theta d. all current branches and voltages

true

vs, vr and vl are all in phase with each other in a parallel rl circuit true or false

inductive reactance

what is the opposition to sinusoidal current in a inductor? impedance, inductive reactance, resistance, power

90 degrees

what phasor relationship between voltage and current in an purely inductive circuit? 90 degrees, 45 degrees do not know

c

what remains constant in a parallel purely inductive circuit no matter what frequency is added? a values of inductors b values of voltage c both

b

what stays the same in a purely inductive series circuit when frequency is increased or decreased? a. current and voltages across inductors or vL b vL and inductor values c power and inductor values d current and VL

increases

when current through an inductor doubles the amount of energy stored in the electromagnetic field decreases, remains constant increases or doubles

true

If inductance value goes up does current decrease? true or false

false

The overall phase angle of a parallel circuit with a resistance of 20 Ω and an inductive reactance of 25 kΩ would be nearly 90° true or false

true

The phase angle follows xl and frequency and impedance in an rl circuit? so does the phase angle increase as frequency increase true or false

loss

What is an eddy current? loss, gain, in between,

Henry

What is the basic unit of inductance? Henry, XL, Ohm, L

L

What is the symbol for inductance? Henry, XL, L, Ohm

faradays law

What law states the amount of voltage induced across a coil is directly proportional to the rate at which the current is changing that causes the phase shift? faradays law,, lenz or murphys law

impedance

What represents the total opposition to sinusoidal current? XL, impedance, XC, R

L circuit

Which circuit does the current lag the voltage by 90 degrees? L circuit, RL Circuit RLC circuit

decreases

a sinosodial voltage is applied across an inductor when the frequency is increased the current, decreases, increases, does not change, goes to zero

down

in a purely inductive series circuit if frequency is increased IT goes down or up

true

in a purely inductive series circuit if frequency is increased XL and XLT goes up true or false

90

in a rl parallel circuit the inductor lags the voltage and the resistor current by ? 45 , 90, 0, 180

true

in a series RL circuit frequency goes up and these go down It, VR true or false

voltage and current

in a series RL circuit the resistor voltage lags the souce ____________ and in phase with ______________

decreased

in a series RL circuit to make the resistor voltage greater than the inductor the frequency is increased, decreased, doubled not a factor

d

A center tap transformer has a connection at the midpoint of the secondary winding resulting in:A. two equal magnitude secondary voltages. B. two 180° out of phase secondary voltages. C. secondary voltages half that of a non-center tapped transformer with the same turns ratio. D. all of these answers are correct.

true

does Kirchhoffs voltage law apply to inductive circuits? true or false

true

does the inductance of an iron core increase if the number of turns increases - true or false

impedance increases

if frequency is raised in a parallel rl circuit what changes

true

in a parallel rl circuit frequency goes up which causes XL and zt values to increase, true or false

true

in a parallel rl circuit if frequency goes up then these go down IT, theta, IL, true or false

b

in a parallel rl circuit the current through the inductor lags the voltage and the resistor current by a 45 degrees b 90 degrees c 180 degrees d -135

true

in a parallel rl circuit vs, vr and vl are in phase at the same magnitude true or false

current and voltage

in a purely inductive circuit increase the frequency causes a decrease in ________ and an in crease in _____________ --- current and voltage, voltage and current, power and resistance

true

in a purely inductive parallel circuit if frequency increases all the currents go down including IT... true or false

true

in a purely inductive parallel circuit if frequency increases xl and xlt increases . true or false