Description : A transformer works on the basic principle of ____________. A. self impedance B. attraction and repulsion C. mutual induction D. increasing power
Last Answer : Answer: C
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 : The device that most commonly utilizes the principle of electromagnetic induction is the _____________. A. diode B. transformer C. transistor D. rheostat
Last Answer : Answer: B
Description : The principle of AC generator is: a. Mutual induction b. self induction c. electromagnetic induction d. Induction
Last Answer : b. self induction
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 : The method used to produce electron emission in most vacuum tubes is known as ____________. A. photoelectric emission B. secondary electric emission C. cold cathodic electric emission D. thermionic emission
Last Answer : Answer: D
Description : A transformer works on the principle of – (1) Self induction (2) Mutual induction (3) Generator (4) Inverter
Last Answer : (2) Mutual induction
Description : A transformer works on the principle of (1) Self induction (2) Mutual induction (3) Generator (4) Inverter
Last Answer : Mutual induction
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 : What are the differences between thermionic emission and evaporation?
Last Answer : Thermionic emission occurs when electron leaves the surface of metals while evaporation occur in liquid when strong electron gain energy and escape the liquid surface in gaseous form
Description : The source of the sun's energy is the process of – (1) Photoelectric emission (2) Nuclear fission (3) Nuclear fusion (4) Thermionic emission
Last Answer : (3) Nuclear fusion Explanation: The Sun formed about 4.6 billion years ago from the gravitational collapse of a region within a large molecular cloud. Most of the matter gathered in the center, ... thermonuclear fusion in its core. It is thought that almost all other stars form by this process.
Description : The source of the Sun's energy is the process of – (1) Photoelectric emission (2) Nuclear fission (3) Nuclear fusion (4) Thermionic emission
Last Answer : (3) Nuclear fusion Explanation: Nuclear fusion is a nuclear reaction in which two or more atomic nuclei join together, or "fuse", to form a single heavier nucleus. During this process, matter ... fusing nuclei is converted to energy which is released. Fusion is the process that powers active stars.
Description : The phenomenon of nuclear fission is opposite to that of (A) Radioactive decay (B) Thermionic emission (C) Nuclear fusion (D) Combustion
Last Answer : (C) Nuclear fusion
Description : The source of the Sun’s energy is the process of (1) Photoelectric emission (2) Nuclear fission (3) Nuclear fusion (4) Thermionic emission
Last Answer : Nuclear fusion
Description : Define Thermionic emission.
Last Answer : The process by which free electrons are emitted from the surface of a metal when external heat energy is applied is called thermionic emission. Thermionic emission occurs in metals that are heated to a very ... of external energy in the form of heat is supplied to the free electrons in the metals.
Description : List any two applications of thermionic emission.
Last Answer : 1. The components which are made by the process of thermionic emission are used in the electronic devices such as cathode ray tube, radio etc. 2. Thermionic emission are used in a ... , power electronics, x-ray generation, and energy converters from high-temperature sources and solar energy.
Last Answer : Thermionic emission occurs in vacuum tubes.
Description : The scientific principle involved in a laser is (a) Newton’s laws of motion (b) Faraday’s laws of induction (c) Motion of a charges particle in an electromagnetic field (d) Amplification by population inversion
Last Answer : Ans:(d)
Description : The voltage at the reference electrode of the circuit shown in the illustration is applied to the input of a/an ______________. EL-0090 A. class A detector whose output drives an ... drives an 2-stage isolation transformer D. magnetic amplifier whose output controls a saturable reactor
Description : Figure 'A' of the diagram shown in the illustration represents a ______________. EL-0092 A. differential transformer B. saturable reactor C. synchro system D. magnetic amplifier
Description : As shown in the illustration, operating the reversing switch will change the polarity of the ______________. EL-0101 A. generator field B. generator armature C. motor armature D. all of the above
Description : Which physical phenomenon or principle is most often applied in the search for petroleum reservoirs? w) magnetic field distortions x) electromagnetic radiation y) natural radioactive decay of minerals z) acoustic wave transmission and reflection
Last Answer : ANSWER: Z -- ACOUSTIC WAVE TRANSMISSION AND REFLECTION
Description : The rotor of a synchronous motor operates in synchronism with the rotating field because ______________. A. of the amortisseur windings B. the rotor is magnetically locked into step with the ... field strength varies directly with rotor slip D. the stator flux rotates in the opposite direction
Description : The application of mutual induction is: a. TV b. Radio c. Transformer d. Motor
Last Answer : c. Transformer
Description : Which common devices works on the basis of the principle of mutual induction? -Do You Know?
Last Answer : answer:
Description : Which common devices works on the basis of the principle of mutual induction?
Last Answer : – Transformer
Last Answer : Transformer
Description : An electrical device which employs a stationary armature and a rotating electromagnetic field is used aboard ship as a ____________. A. magnetic amplifier B. ship's service alternator C. three-wire DC generator D. saturable core reactor
Description : What are the use of mutual induction and self-induction?
Last Answer : Use of mutual induction a. Transformers are works on this principle. b. An inductance furnace makes use of it. c. Used in ignition coils of motor car, motor cycles, scooters etc. Use of ... 's normal working time. c. Used in welding plant rectifiers to keep arc stationary by smoothing choke.
Description : Quartz crystal in quartz watches work on the principle called? A. Photoelectric effect B. Stark effect C. Thermionic effect D. Piezo-electric effect (Answer) E. None of these
Last Answer : D. Piezo-electric effect (Answer)
Description : 27] In a transformer, the leakage flux of each winding is proportional to the current in that winding because A. Ohm's law applies to magnetic circuits B. Leakage paths do no saturate C. the two windings are electrically isolated D. mutual flux is confined to the core
Last Answer : B. Leakage path do not saturate
Description : 12] Which is not the basic element of the transformer? A. core B. primary winding C. secondary winding D. mutual flux
Last Answer : D. Mutual flux
Description : A three-phase, squirrel cage, induction motor will run hot due to a/an ______________. A. improper brush position B. reversed commutating pole C. shorted stator D. high power factor
Description : The reversal of an AC, three-phase, induction motor is accomplished by ______________. A. changing all three motor leads B. reversing the position of the slip rings C. interchanging any two of the three motor leads D. interchanging any two brushes
Description : In general, polyphase induction motors can be started on full line voltage by means of ______________. A. compensator starters B. autotransformer starters C. across-the-line starters D. primary-resistor starters
Description : If your multimeter gives a reading in ohms when testing each end of each conductor of a three-conductor cable, this indicates ______________. A. continuity of the conductor B. an infinite resistance C. the presence of a partial ground D. that the conductor is not short circuited
Last Answer : Answer: A
Description : If you disconnect and arrange both ends of a three conductor cable, without any contact between the individual conductors, an indicated ohmic value between the ends of a single conductor would indicate ... resistance C. the presence of a partial ground D. that the conductor is not short circuited
Description : The action of electromagnetic machines can be related to which ofthe following basic principles ? (a) Induction (b) Interaction (c) Alignment (d) All of the above
Last Answer : (d) All of the above
Description : In a three-phase, squirrel-cage type, induction motor the rotating magnetic field is established by the _____________. A. current induced in the rotor windings B. application of a three-phase voltage ... caused by the induced current in the squirrel-cage bars with the magnetic field of the stator
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 : The most common source of excitation for synchronous motors is a/an ______________. A. stepup transformer B. half-wave rectifier C. DC supply D. AC supply
Description : Which of the listed electrical devices is represented by the symbol shown in the illustration? EL-0055 A. Fixed resistance resistor B. Coil with magnetic core C. DC motor or generator shunt field D. Transformer
Description : In addition to testing the calibration of a circuit breaker, maintenance should include all of the following EXCEPT ______________. A. changing out of magnetic elements and thermal heaters yearly B. ... for loose or missing parts D. making sure foreign matter does not block tripping element
Description : Voltage will always lead current in a/an ______________. A. capacitive circuit B. inductive circuit C. magnetic circuit D. resistive circuit
Description : Magnet chatter or 'pumping' occurring in a magnetic contactor can be caused by ______________. A. dirt or grease on pole faces B. mechanical interference in the contacts C. chattering contacts on the control relay D. magnetic lock out of the contacts
Description : Find the mobility of the conduction electrons in a copper conductor if in Hall effect measuremaents performed in the magnetic fileld of induction `B =
Last Answer : Find the mobility of the conduction electrons in a copper conductor if in Hall effect measuremaents ... than that of the longtudinal electric field.
Description : To increase the frequency of an operating AC generator, you should ____________. A. increase the field excitation B. decrease the field excitation C. increase the number of magnetic poles D. increase the speed of the prime mover
Description : Which of the following statements is true concerning the operating characteristics of a squirrel-cage motor? A. Rotor slip is dependent upon the motor load. B. An increase in motor load results in ... results in less generated current. D. A decrease in rotor speed produces a weaker magnetic field.
Description : An α particle moves perpendicular to a constant magnetic field of strength 1.2 T in a circular path of radius 0.7 m. The speed of α particle in ms-1 is ______________ a) 2.7 × 107 b) 2.6 × 107 c) 3.2 × 107 d) 2.0 × 107
Last Answer : a) 2.7 × 107
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