Description : What device sweeps a band of frequencies to determine frequencies and amplitudes of each frequency component?
Last Answer : Spectrum analyzer.
Description : What is a nonrotating device that produces alternating current?
Last Answer : Oscillator.
Description : How would the compass react if the alternating current through the conductor was a high frequency?
Last Answer : The compass needle would vibrate rapidly around the zero current point ac meter (magnetic north).
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 : 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 : 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
Last Answer : Answer: B
Description : What is the name of the device used to convert alternating current into direct current ? (1) Ammeter (2) Galvanometer (3) Rectifier (4) Transformer
Last Answer : Rectifier
Description : A cavity that vibrates at its natural frequency produces a louder sound than at other frequencies. What term is used to describe this phenomenon?
Last Answer : Resonance.
Description : What are electromagnetic waves? A. Alternating currents in the core of an electromagnet B. A wave consisting of two electric fields at right angles to each other C. A wave consisting of an electric field ... to each other D. A wave consisting of two magnetic fields at right angles to each other
Last Answer : C. A wave consisting of an electric field and a magnetic field at right angles to each other
Description : What are electromagnetic waves? A. A wave consisting of two magnetic fields at right angles to each other B. A wave consisting of an electric field and a magnetic field at right angles to each ... core of an electromagnet D. A wave consisting of two electric fields at right angles to each other
Last Answer : B. A wave consisting of an electric field and a magnetic field at right angles to each other.
Description : When a wide band of frequencies is transmitted simultaneously, each frequency will vary in the amount of fading. What is this variable fading called?
Last Answer : Selective fading.
Description : What term is used to describe the frequency at which the filter circuit changes from the point of rejecting the unwanted frequencies to the point of passing the desired frequencies?
Last Answer : Frequency cutoff (fco).
Description : How are alternating currents produced?
Last Answer : What is the answer ?
Description : Currents that flow in circles inside a disc are known as A. eddy currents B. circular currents C. air currents D. alternating curent
Last Answer : eddy currents
Description : Alternating voltages and currents are represented by straight line with an arrow to represent the magnitude and direction. This representation is called
Last Answer : Alternating voltages and currents are represented by straight line with an arrow to represent the magnitude and direction. This representation is called Phasor quantity
Description : Define alternating current.
Last Answer : An electrical current which is constantly varying in amplitude, and which changes direction at regular intervals.
Description : Current flowing in only one direction is called ___________. A. alternating current B. omnidirectional current C. direct current D. sinusoidal current
Last Answer : Answer: C
Description : What is the band of frequencies called that is included between the two points at which current falls to 70 percent of its maximum value in a resonant circuit?
Last Answer : Bandwidth of the circuit
Description : The following are true about electroretinogram: a. the a-wave is produced by the photoreceptors b. the b-wave is produced by the ganglion cells c. c-wave is produced by the retinal pigment epithelium d. different light frequencies can be used to separate rod and cone respons
Last Answer : he a-wave is produced by the photoreceptors
Description : The following are true about electroretinogram: a. the a-wave is produced by the photoreceptors b. the b-wave is produced by the ganglion cells c. c-wave is produced by the retinal pigment epithelium d. different light frequencies can be used to separate rod and cone response
Last Answer : the a-wave is produced by the photoreceptors
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 : 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 : 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 : 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 : 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
Last Answer : Answer: A
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
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 : 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
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
Description : Alternating current is converted into direct current by using –
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 : A transformer works with (1) alternating current only (2) direct current only (3) both AC and DC (4) any signal
Last Answer : alternating current only
Description : Alternating current is converted into direct current by a (1) transformer (2) dynamo (3) oscillator (4) rectifier
Last Answer : rectifier
Description : Describe the difference between direct and alternating current.
Last Answer : Direct current is the flow of electricity or charge in one direction.. Alternative current is the flow of charge that doesn't flow in one direction.
Description : A 1000W heater is rated to operate at a direct current (DC) of 10A. If the heater is supplied alternating current (AC) for producing the same quantity of heat the value of current should be a. Iav=10A b. Irms=10A c. Ipeak=10A
Last Answer : A 1000W heater is rated to operate at a direct current (DC) of 10A. If the heater is supplied alternating current (AC) for producing the same quantity of heat the value of current should be Irms=10A
Description : What type filter is used to block the passage of current for a narrow band of frequencies, while allowing current to flow at all frequencies above or below this band?
Last Answer : . Band-reject.
Description : How does transit time affect the relationship of the grid voltage and the plate current at high frequencies?
Last Answer : Transit time causes the grid voltage and plate current to be out of phase
Description : The cavities of a multicavity klystron are tuned to slightly different frequencies in what method of tuning?
Last Answer : Stagger tuning.
Description : Besides a method of trial and error, which of the following methods is employed for solution of network problems in interconnected system ? (a) Circulating current method (b) Thevenin's theorem (c) Superposition of currents (d) Direct application of Kirehhoffs laws (e) All of the above
Last Answer : (e) All of the above
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.
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 : What type filter is used to allow a narrow band of frequencies to pass through a circuit and attenuate all other frequencies above or below the desired band?
Last Answer : Bandpass.
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 is the filter called that passes low frequencies but rejects or attenuates high frequencies?
Last Answer : Low-pass filter, high-frequency discriminator or high-frequency attenuator.
Description : What is the filter called in which the low frequencies do not produce a useful voltage?
Last Answer : High-pass filter, low-frequency discriminator, or low-frequency attenuator.
Description : Space diversity transmission means transmitting and receiving on _______. A. Two or more antennas operating on two different frequencies B. Two or more identical frequencies C. Two or more antennas operating on the same frequency D. Two or more different frequency
Last Answer : C. Two or more antennas operating on the same frequency