Description : When a megohmmeter is used to test insulation, the gradual rise of the pointer reading as a result of continued cranking, is caused by _____________. A. good conductor resistance B. the ... insulation C. the inductive reactance of the windings D. the dielectric-absorption effect of the insulation
Last Answer : Answer: D
Description : The twisting force developed by a motor and applied to a shaft is called _____________. A. magnetism B. electromotive force C. torque D. voltage
Last Answer : Answer: C
Description : Electric current is the flow of electrons through a conductor; the rate of this flow is measured in ___________. A. volts B. amperes C. coulombs D. ohms
Last Answer : Answer: B
Description : Electric current is the flow of electrons through a conductor. The rate of this flow is measured as ___________. A. volts/watt B. amperes/centimetre C. coulombs/second D. ohms/volt
Description : A 'dielectric' is a/an ________________. A. electrical insulator B. current flow C. good conductor D. semiconductor material
Last Answer : Answer: A
Description : What is the function of the interpoles installed in DC motors? A. To provide greater torque by strengthening the main field. B. To provide sparkless commutation without having to shift the brushes. C. To limit the production of counter-electromotive force. D. To limit the starting surge current.
Description : The amount of mechanical force or torque produced by an electric motor depends on the ________________. A. strength of its magnetic field B. amount of armature current flow C. length of conductor in the field D. all of the above
Description : Capacitors can be used in electric distribution systems to improve power factor. This is accomplished by seesawing energy between the capacitor and the _____________. A. generator B. inductive loads C. resistive loads D. all of the above
Description : To properly use a hook-on-type volt/ammeter to check current flow, you must FIRST _____________. A. de-energize the circuit to allow connection of the instrument in series B. hook the jaws ... test leads to the appropriate terminals D. short the test leads and calibrate the instrument to zero
Description : The ratio of the effective value of the counter EMF in volts, to the effective value of the current in amperes is called _____________. A. impedance factor B. capacitive reactance C. inductive reactance D. root mean square
Description : How electromotive force is created in a generator?
Last Answer : When a conductor cuts the magnetic lines of forces, an Electro motive force (emf) is generated. The magnitude of the generated voltage is directly proportional to the rate of change at which a conductor cuts the magnetic lines of force.
Description : Compute the conductivity when the current density is 12 units and the electric field is 20 units. Also identify the nature of the material. a) 1.67, dielectric b) 1.67, conductor c) 0.6, dielectric d) 0.6, conductor
Last Answer : c) 0.6, dielectric
Description : A megohmmeter is used to measure _____________. A. voltage B. dielectric strength C. current D. power
Description : When a megohmmeter is used to test the dielectric strength of wire insulation, the initial dip of the pointer toward 'zero' is caused by _____________. A. good insulation B. the leakage of ... of dirty insulation C. the capacitance of the circuit D. the dielectric absorption effect of the insulation
Description : A semi-conductor is damaged & behaves like a conductor, on passing a strong electric current through it, because it heats up the crystals & breaks the covalent bonds resulting in __________ electrons. (A) Lack of free (B) Excess of (C) Decrease in (D) None of these
Last Answer : (B) Excess of
Description : A fuse will 'blow' if _____________. A. an electric motor is stopped suddenly by opening a switch B. the flow of current to the protection device is reversed C. the electrical current exceeds the rated value of the fuse D. unequal resistors are connected in parallel
Description : Inductance is the property of an electric circuit that _____________. A. opposes any change in the applied voltage B. opposes any change in the current flow through the circuit C. aids any changes in the applied voltage D. aids any changes in the current through the circuit
Description : The unit of apparent power in a purely inductive circuit is called the _____________. A. kva B. var C. emf D. watt
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 process, whereby electrons gain sufficient energy to be released from the surface of a thin, heated metal plate, is known as _____________. A. photo electric emission B. secondary emission C. thermionic emission D. regressive emission
Description : AC circuits develop resistance, inductance, and capacitance. The inductive reactance of a circuit is expressed in _____________. A. ohms B. mhos C. henrys D. farads
Description : The combined effect of inductive reactance, capacitive reactance, and resistance in an AC series circuit is known as _____________. A. reactance B. total reactance C. impedance D. resonance
Description : The apparent power in a purely inductive circuit is also known as _____________. A. true power B. lead power C. induced power D. reactive power
Description : In an induction motor, rotor currents are circulated in the rotor by _____________. A. slip rings and brushes B. an armature and brushes C. inductive reaction of the rotating stator field D. external variable resistors
Description : What is the dependence of mechanical force per unit area of charged conductor on the surface charge density and the dielectric constant of the medium
Last Answer : What is the dependence of mechanical force per unit area of charged conductor on the surface charge density and the dielectric constant of the medium
Description : A megger is being used to test the insulation of an AC generator. The resistance value of a dry, clean winding will _____________. A. continue to rise as test potential is maintained, ... , becoming fairly steady after 5-7 minutes D. stabilize after approximately 2-4 minutes of fluctuation
Description : A saturable-core reactor operates on the principle of controlling a load winding's inductance by varying the core's _____________. A. dielectric B. permeability C. reactance D. inductance
Description : A current-carrying conductor making electrical contact with a wiring conduit will be indicated by a _____________. A. high switchboard wattmeter reading B. totally dark switchboard ground detecting light C. low switchboard wattmeter reading D. all of the above
Description : A current-carrying conductor makes accidental contact with a wiring conduit. This will be indicated by a _____________. A. low switchboard wattmeter reading B. high switchboard wattmeter reading C. darkened switchboard ground detecting lamp D. darkened switchboard synchronizing lamps
Description : A current carrying conductor making an electrical contact with a wiring metal conduit is indicated by a _____________. A. low switchboard wattmeter reading B. reading of 1.0 on the power factor meter C. high switchboard voltmeter reading D. totally darkened switchboard ground-detecting light
Description : What is the meaning of ' electromotive force 1.5 volts' of a dehydrated cell ?
Last Answer : The electromotive force of a dehydrated cell is 1.5 volts' , which means 1.5 joules of electricity to conduct 1 coulomb of electricity from the positive pole of the cell to the negative pole .
Description : Two cells connected in series have electromotive force of 1.5 V each. Their internal resistances are `0.5 Omega` and `0.25 Omega` respectively. This c
Last Answer : Two cells connected in series have electromotive force of 1.5 V each. Their internal ... potential differnce across the terminals of each cell.
Description : What is the difference between voltage and electromotive force?
Last Answer : Need answer
Description : Find the force that exists in an electromagnetic wave. a) Electrostatic force b) Magnetostatic force c) Lorentz force d) Electromotive force
Last Answer : c) Lorentz force
Description : According to Faraday’s law, EMF stands for a) Electromagnetic field b) Electromagnetic force c) Electromagnetic friction d) Electromotive force
Last Answer : d) Electromotive force
Description : Gilbert is a unit of (a) electromotive force (6) magnetomotive force (c) conductance (d) permittivity
Last Answer : (6) magnetomotive force
Description : The loss tangent refers to the a) Power due to propagation in conductor to that in dielectric b) Power loss c) Current loss d) Charge loss
Last Answer : a) Power due to propagation in conductor to that in dielectric
Description : What is the name of the force that causes electrons to move away from the nucleus?
Description : Out of the following methods of heating the one which is independent of supply frequency is (A) electric arc heating (B) induction heating (C) electric resistance heating (D) dielectric heating
Last Answer : (C) electric resistance heating
Description : What makes electrons move through a conductor in only one direction?
Last Answer : What is the answer ?
Description : The current through a metallic conductor is due to the motion of a. free electrons b. Protons c. Neutrons d. still under controversy
Last Answer : a. free electrons
Description : (2) experience collision less frequently Explanation: When an electric field is applied, both the valence electrons and the free electrons move in the same direction. The hole direction is opposite to that ... to free electrons. This means mobility is also less for a hole compared to free electron.
Last Answer : Carbon dioxide is called a greenhouse gas because - (1) its concentration remains always higher than other gases (2) it is used in photosynthesis (3) it absorbs infrared radiation (4) it emits visible radiation
Description : The left hand rule correlates to (a) current, induced e.m.f. and direction of force on a conductor (b) magnetic field, electric field and direction of force on a conductor (c) self induction, ... and direction of force on a conductor (d) current, magnetic field and direction of force on a conductor
Last Answer : (d) current, magnetic field and direction of force on a conductor
Description : Basic electrical motor action depends on _______________. A. a conductor rotated within a magnetic field B. a current carrying conductor placed in a magnetic field C. the relative force of the commutator and commutating poles D. the relative force of the armature and interpoles
Description : The insulation of electric generators during short idle periods should be _____________. A. allowed to cool slowly to ambient temperatures B. flashed with direct current to remove any residual ... using strip or space heaters D. relieved of all capacitive charge by grounding the conductors
Description : Universal motors will operate on AC or DC current, and are generally found in _____________. A. portable tools B. large pump motors C. turbo electric main motors D. forced draft fans
Description : An electrical connection between the wiring of an electric motor and its metal frame is known as a/an _____________. A. eddy current B. ground C. impedance D. flux leakage
Description : Capacitance is the property of an electric circuit opposing a change in the _____________. A. current in the circuit B. voltage in the circuit C. inductance in the circuit D. resistance in the circuit
Description : The purpose of DC generator brushes is to _____________. A. neutralize armature reaction B. conduct electric current to an outside circuit C. convert DC current to AC current D. provide excitation to a DC generator
Description : The full torque electric brake on an electric cargo winch functions to _____________. A. act as a backup brake in the event the mechanical brake should fail B. automatically hold the load ... automatically govern the lowering speed of the load D. automatically govern the hoisting speed of the load