eddy currents
Description : Reversing the current flow through a coil will ___________. A. reduce the amount of flux produced B. have no effect on the eddy currents produced C. reduce the power consumed D. reverse its two-pole field
Last Answer : Answer: D
Description : If overloading a DC machine becomes necessary in an emergency, you should ____________. A. cool the machine with portable blowers and fans B. hold thermal overload relays open with blocks of ... the windings for cooling D. increase the residual magnetism value of windings to reduce eddy currents
Last Answer : Answer: A
Description : Brush sparking during commutation may be caused by ________. A. eddy currents in the armature core B. laminations in the generator field pieces C. induced current opposite to coil inductance D. coil inductance discharge occurring at commutation
Description : Transformer cores are laminated to reduce _____________. A. eddy currents B. secondary flux C. leakage flux D. all of the above
Description : On tank vessels with an electrically-driven capstan, the motor should be meggered periodically to test _____________. A. insulation resistance B. eddy currents C. capacitance D. armature reactance
Description : Diamagnetic materials are magnetised (A) Strongly (B) Only slightly (C) With eddy currents only (D) In a direction opposite to that of the applied field
Last Answer : (D) In a direction opposite to that of the applied field
Description : Diamagnetic materials (A) Are magnetised by eddy currents only (B) Are non-magnetic and cannot be magnetised (C) Are magnetised in direction opposite to the magnetic field (D) Can be magnetised in one direction only
Last Answer : (C) Are magnetised in direction opposite to the magnetic field
Description : Eddy currents produced in the core of transformer are responsible for: a. heat loss b. Step up process c. Step down process d. induction phenomena
Last Answer : d. induction phenomena
Description : 69 In case there are burrs on the edges of the laminations of the transformer, it is likely to result in A. Vibrations B. Noise C. Higher eddy currents loss D. Higher hysteresis loss
Last Answer : C. Higher eddy currents loss
Description : Eddy currents are induced in the pole shoes of a D.C. machine due to?
Last Answer : Eddy currents are induced in the pole shoes of a D.C. machine due to relative rotation between field and armature.
Description : How are alternating currents produced?
Last Answer : What is the answer ?
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 : 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 : 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
Last Answer : The disc of an instrument using eddy current damping should be of conducting and non-magnetic material.
Description : A long wire carries a steady curent . It is bent into a circle of one turn and the magnetic field at the centre of the coil is `B`. It is then bent in
Last Answer : A long wire carries a steady curent . It is bent into a circle of one turn and the magnetic field at the centre of ... ^(2)B` C. `2nB` D. `2n^(2)B`
Description : A square coil of edge I having n turns carries a curent i. it is kept on a smooth horizontal plate. A uniform magnetic field B exists in a direction p
Last Answer : A square coil of edge I having n turns carries a curent i. it is kept on a smooth horizontal plate. A uniform ... . `(Mg)/(4niL)` D. `(2Mg)/(niL)`
Description : The eddy diffusivity for a liquid in plug flow must be (A) 1 (B) 0 (C) ∞ (D) Between 0 and 1
Last Answer : (B) 0
Description : On heating a circular metallic disc with a circular hole at the centre, the diameter of the hole will (a) decrease (b) remain the same (c) increase (d) first increase, then decrease
Last Answer : Ans:(c)
Description : A circular disc of radius 5m with a surface charge density ρs = 10sinφ is enclosed by surface. What is the net flux crossing the surface? a) 3 b) 2 c) 1 d) 0
Last Answer : d) 0
Description : The valve fitted closely in a recess against an opening in a pipe, is generally (A) Wedge shaped circular disc (B) Spherical disc (C) Parallelepiped disc (D) Conical shaped circular disc
Last Answer : (A) Wedge shaped circular disc
Description : is a circular concave revolving steel plate using for cutting and inverting the soil. a. Gang bolt. c. Disc b. Bearing d. None
Last Answer : Bearing
Description : The high voltage winding is usually which of the following type ? (a) Cylindrical winding with circular conductors (b) Cross-over winding with either circular or small rectangular conductors (c) Continuous disc type winding with rectangular conductors (d) All of the above types
Last Answer : (d) All of the above types
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 rotor slots of a repulsion-type motor are generally skewed (placed nonparallel to the rotor axis) to _________. A. produce a constant starting torque B. permit a greater air gap with the starter C. permit a smaller air gap with the starter D. reduce eddy current losses
Description : Pick out the wrong statement. (A) The mass diffusivity, the thermal diffusivity and the eddy momentum diffusivity are the same for NSc = NPr= 1 (B) 1 Nm3 of dry air is lighter ... ) The Lewis number of a mixture is unity, when the thermal diffusivity is equal to the mass diffusivity
Last Answer : (B) 1 Nm3 of dry air is lighter than 1Nm3 of humid air
Description : There's a target in my arrow; or rather, a pattern of alternating light and dark bands. Why?
Last Answer : answer:Reminds me of the way they make steel for swords. You take layers of high carbon and low carbon iron and pound them together, fold them over, and pound again, and do this over and ... tothe solution is approximately 8 cubic centimeters. This sounds kind of like what you're talking about.
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 : 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 : Graph of alternating current is a A. cos wave B. tan wave C. curve D. sine wave
Last Answer : sine wave
Description : In transformer, alternating current is induced inA. primary coil B. secondary coil C. iron core D. resistor
Last Answer : primary coil
Description : Equation which measures alternating voltage is A. Vsin ω B. sin t C. Vo sinωt D. V=IR
Last Answer : Vo sinωt
Description : The doorbell on your house requires a 12 volt alternating current. A transformer having a primary winding of 1,600 turns is to be used to step down your house's 110-volt alternating current. How many turns are there on the secondary winding?
Last Answer : ANSWER: 175 TURNS
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 : 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 : The magnetic field produced by a long straight wire carrying a current points: w) in the direction of the current x) toward the wire y) away from the wire z) circles around the wire
Last Answer : ANSWER: Z -- CIRCLES AROUND THE WIRE
Description : A copper rod which is 1 centimeter in diameter carries a current of 5 amps. The current is distributed uniformly throughout the rod. The magnetic field half way between the axis of the rod and its ... ) zero. x) pointing radially outward y) pointing radially inward z) circles the axis of the rod
Last Answer : ANSWER: Z -- CIRCLES THE AXIS OF THE ROD
Description : An infinitely long wire carries a current of three amps. The magnetic field outside the wire: w) points radially away from the wire x) points radially inward y) circles the wire z) is zero.
Last Answer : ANSWER: Y -- CIRCLES THE WIRE
Description : ____ heating means that the circulation of currents in one region inside a can distributes the heat to another. a. Conduction c. Convection b. Radiation d. Slow
Last Answer : c. Convection
Description : What is transported when warm ocean currents cool as they flow along the coastline away from the equator?
Last Answer : Water
Description : A flow of electric currents?
Last Answer : lighting
Description : Extensive deserts occur in the western tropical regions of continents because : (1) of easterly trade winds. (2) cold ocean currents flow along the western coasts. (3) of the effect of both the ... winds and cold ocean currents. (4) the rate of evaporation is greater along the western margin areas.
Last Answer : (3) of the effect of both the off-shore easterly trade winds and cold ocean currents. Explanation: Extensive deserts occur in the western tropical regions of continents because of the effect of ... is found near the tropics of Cancer and Capricorn, usually toward the western side of the continents
Description : Dilution method of disposing of sewage, is not preferred to A. When sewage is fresh B. When diluting water has high dissolved oxygen content C. When diluting water is used for water supply near the point of sewage disposed D. When the diluting water is having flow currents
Last Answer : ANS: C