Description : How would a compass react when placed close to a conductor carrying alternating current at a low frequency?
Last Answer : The compass needle would swing back and forth as the current changed from positive to negative.
Description : How does a compass react when placed close to a current carrying conductor?
Last Answer : The compass needle swings away from magnetic north and aligns itself with the magnetic field around the conductor
Description : What is the device called that will separate alternating current from direct current, or that will separate alternating current of one frequency from other alternating currents of different frequencies?
Last Answer : A filter.
Description : What is a nonrotating device that produces alternating current?
Last Answer : Oscillator.
Description : Define alternating current.
Last Answer : An electrical current which is constantly varying in amplitude, and which changes direction at regular intervals.
Description : How does a capacitor and an inductor react to (a) low frequency and (b) high frequency?
Last Answer : At low-frequency, a capacitor acts as an open and an inductor acts as a short. At high-frequency, a capacitor acts as a short and an inductor acts as an open.
Description : A sinusoidally alternating current of frequency 60 Hz has a maximum value of 15 A. Find the value of current after 1/200 second
Last Answer : A sinusoidally alternating current of frequency 60 Hz has a maximum value of 15 A. Find the value of current after 1/200 second
Description : Which of the following statements concerning AC circuits is correct? A. The power factor of a resistive circuit is always zero. B. True power in an inductive circuit always equals apparent power. ... . D. Total opposition to the flow of alternating current depends upon the amount of reactive power.
Last Answer : Answer: C
Description : The reactance offered by a capacitor to an alternating current of frequency 50 Hz is 10 ohm. If frequency is increased to 100 Hz, the reactance will be (a) 2.5 ohm (b) 5.0 ohm (c) 20.0 ohm (d) 40.0 ohm
Last Answer : Xc = 1/(2*pi*f*c) so when f is double .... Xc will be half ... Ans is 5ohm
Description : The frequency of an alternating current is?
Last Answer : The frequency of an alternating current is the number of waves passing through a point in one second.
Description : The reactance offered by a capacitor to alternating current of frequency 50 Hz is 20 Q. If frequency is increased to 100 Hz, reactance becomes_____ohms.
Last Answer : The reactance offered by a capacitor to alternating current of frequency 50 Hz is 20 Q. If frequency is increased to 100 Hz, reactance becomes 10 ohms.
Description : A compass is located at the geographical North Pole. In which direction would its needle point?
Last Answer : To the magnetic north pole.
Description : If the alternating source in Q41 is changed to 200 volts peak-to-peak, what is Iavg?
Last Answer : Iavg = 0.636 × Imax = 1.41 amperes.
Description : What causes the current-carrying area at the center conductor of a coaxial line to be restricted to a small layer at the surface?
Last Answer : Skin effect.
Description : If the amount of current in the conductor changes, what happens to the magnetic field around the conductor?
Last Answer : If the current increases the magnetic field increases; if the current decreases the magnetic field decreases.
Description : The method of magnetization is: (1) hammering a magnet (2) heating a magnet (3) passing direct current through it (4) passing alternating current through it
Last Answer : (1) hammering a magnet Explanation: Hammering a rod will either allow it to become slightly magnetic inlaid along a magnetic field (i.e.North - South) or demagnetize it if laid across the field lines (i.e. East-West). A current passing through a coil will produce a magnetic field.
Description : The charge of a lead-acid battery can be restored by ______. A. passing an alternating electric current through the cell B. passing a direct electric current through the cell C. adding acid to the electrolyte D. all of the above
Last Answer : Answer: B
Description : The method of magnetisation is: (1) hammering a magnet (2) heating a magnet (3) passing direct current through it (4) passing alternating current through it
Last Answer : hammering a magnet
Description : When an alternating current passes through an ohmic resistance the electrical power converted into heat is?
Last Answer : When an alternating current passes through an ohmic resistance the electrical power converted into heat is true power.
Description : Can you make alternating current through a battery?
Last Answer : Yes, we can make AC through a battery using an inverter.
Description : Type of power-line frequency meter composed of vibrating iron reed placed in alternating magnetic field
Last Answer : Vibrating Reed Type
Description : (a) Define permeability. (b) Define MMF. (c) Define form factor of an alternating quantity. (d) Define frequency and time period of an alternating quality. (e) Define transformation ratio of transformer. ... and state the meaning of each term used. (g) Give two applications of single phase motors.
Last Answer : Permeability : It is the ability of a magnetic/Non magnetic material to allow setting up of flux in it. MMF : The magneto motive force (MMF) is the force required to setup flux in a magnetic / ... applications of single phase motors : Water pumps, ceiling fan, lathe machine
Description : What will be the phase angle between two alternating waves of equal frequency, when one wave attains maximum value the other is at zero value ?
Last Answer : 90° will be the phase angle between two alternating waves of equal frequency, when one wave attains maximum value the other is at zero value.
Description : Rectifiers are used to convert - (1) Direct current to Alternating current (2) Alternating current to Direct current (3) high voltage to low voltage (4) low voltage to high voltage
Last Answer : (2) Alternating current to Direct current Explanation: Converting DC power from one voltage to another is much more complicated. One method of DC-to-DC conversion first converts power to AC (using a ... inverter), then uses a transformer to change the voltage, and finally rectifies power back to DC.
Description : Coast Guard Regulations (46 CFR) require that each alternating current generator arranged for parallel operation shall be provided with _____________. A. more than one means of excitation B. individual circuit fuses C. a high back-pressure trip D. a reverse-power trip
Last Answer : Answer: D
Description : The use of four diodes, in a full-wave bridge rectifier circuit, will __________. A. provide unidirectional current to the load B. allow a very high leakage current from the load C. convert direct current to alternating current D. offer high opposition to current in two directions
Last Answer : Answer: A
Description : One method of testing for a reversed shunt field coil in a DC generator or motor is by connecting the field to a direct current source, at reduced field rated voltage, and test for ... placed near each field C. test lamp across adjacent fields D. copper jumper across the interpole connections
Description : How does each type of trip element react to an overload?
Last Answer : he thermal trip element makes use of a bimetallic element that bends with an increase in temperature or current. The bending causes the trip bar to be moved releasing the latch.
Description : What value does a meter movement react to (actually measure) when measuring ac?
Last Answer : Average value.
Description : hat establishes the value of the current that flows in the output of figure 4-43?
Last Answer : The frequency of the voltage input.
Description : What is the difference between alternating current and direct current?
Last Answer : Direct current is a constant flow of electrons in one direction. Alternating current means that the current moves back and forth and transfers the electricity that way. DC is typically used with battery power and AC is used for long distance electricity transportation.
Description : 3. Which sources produce alternating current? -Physics-10
Last Answer : Power plants and AC generators are some of the sources that produce alternating current.
Description : What is Alternating Current ( AC) ?
Last Answer : An alternating current is a current that changes direction as it flows and its value changes every moment . We can get alternating current from alternators.
Description : What is Alternating Current ?
Last Answer : An alternating current is a current that changes direction as it flows, and its value changes every moment.
Description : Which of the following statements about continuous cardiac output monitoring are true? A. Continuous cardiac output monitoring may unmask events not detected by intermittent cardiac output measurements. ... stroke volume by detecting changes in resistance to a small, applied alternating current.
Last Answer : Answer: AD DISCUSSION: Various techniques are available to measure cardiac output continuously. The advantages of continuous cardiac output monitoring, as compared with intermittent methods, are (1) ... function of the stroke volume, which then can be used to calculate the cardiac output
Description : What is the name of the device used to convert alternating cur-rent into direct current? (1) Amreter (2) Galvanometer (3) Rectifier (4) Transformer
Last Answer : (3) Rectifier Explanation: A rectifier is an electrical device that converts alternating current (AC), which periodically reverses direction, to direct current (DC), which flows in only one direction. The process is known as rectification.
Description : Alternating current is converted into direct current by a – (1) Transformer (2) Dynamo (3) Oscillator (4) Rectifier
Last Answer : (4) Rectifier Explanation: A rectifier is an electrical device that converts alternating current (AC), which periodically reverses direction, to direct current (DC), which flows in only one direction. The process is known as rectification.
Description : When a megohmmeter is being used on a alternating current machine, the meter pointer will dip toward 'zero' and then gradually rise to the true resistance value if the motor insulation is _____________. A. grounded B. good C. shorted D. dirty
Description : In an alternating current electrical system, a low system power factor is a direct sign of _____________. A. wasted energy B. efficient operation C. a short in the exciter field windings D. an excessive number of minor system grounds
Description : Current flowing in only one direction is called ___________. A. alternating current B. omnidirectional current C. direct current D. sinusoidal current
Description : A device used in an electrical circuit to change alternating current to direct current, is known as a _____________. A. current transformer B. rectifier C. condenser D. shunt
Description : If many turns of an alternating current coil for a contactor become short circuited, the coil _____________. A. will continue to operate B. will probably burn out immediately C. will operate on reduced current D. temperature will drop
Description : Which of the listed devices may be installed on a large diesel-electric alternating current propulsion generator? A. Temperature detector coils inserted in the stator slots for measuring stator temperature. B. ... . C. Electric space heaters to prevent condensation of moisture. D. All of the above.
Description : If many turns of an alternating current coil for a contactor become short circuited, the coil _____________. A. temperature will drop B. will probably burn out immediately C. will continue to operate D. will operate on reduced current
Description : Possible phase relationships between voltage and current in an alternating current circuit include which of the following conditions? A. Current and voltage may be in phase. B. Current may lead the voltage. C. Current may lag the voltage. D. All of the above.
Description : Which of the following components are used to convert alternating current produced in the generator windings to direct current? A. Armature and equalizer B. Commutator and brushes C. Rotor and interpoles D. Field and exciter
Description : Alternating current circuits develop resistance, inductance, and capacitance. The capacitance of individual capacitors is expressed in _____________. A. ohms B. mhos C. henrys D. farads
Description : Alternating current circuits develop resistance, inductance and capacitance. The inductance of a coil is expressed in _____________. A. ohms B. mhos C. henrys D. farads
Description : The purpose of the commutator and brushes on a DC generator is to _____________. A. transfer generated direct current voltage from the armature to the line B. convert the alternating voltage ... contact method to excite the field D. reduce sparking between the armature and the carbon brushes