Question Bank 13 Flashcards
An operation in which the motor runs when the push button is pressed and will stop when the push button is released. A. Clipping B. Jogging C. Plugging D. Commissioning
B. Jogging
It is not advisable to leave a lead acid storage battery in a discharged state for a long time mainly because A. the plates will become sulphated B. electrolyte will attack the condenser C. electrolyte will become weak D. acid will evaporate
A. the plates will become sulphated
An instrument used to measure temperature. A. Thermometer B. Tachometer C. Synchroscope D. Thermocouple
A. Thermometer
What is the angular velocity for a 25-cycle circuit? A. 3.1416 radians per second B. 157 radians per second C. 377 radians per second D. 314 radians per second
B. 157 radians per second
A term universally employed to measure wire diameters. A. Millimeter B. Circular mil C. Meter D. Mil
D. Mil
In a radio, gang condenser is a type of A. electrolytic capacitor B. paper capacitor C. ceramic capacitor D. air capacitor
D. air capacitor
To keep the terminals of a lead-acid storage battery free from corrosion, it is advisable to
A. keep electrolyte level low
B. apply petroleum jelly
C. charge the battery at frequent intervals
D. clean the terminals frequently
B. apply petroleum jelly
A \_\_\_\_\_ is a device with functions that is similar to a rectifier. A. transformer B. contactor C. inverter D. commutator
D. commutator
Which of the following is a typical usage of an autotransformer? A. Motor control transformer B. Grounding transformer C. Distribution transformer D. Multi-voltage transformer
D. Multi-voltage transformer
The electrolyte used in carbon-zinc dry cell is a combination of \_\_\_\_\_ dissolved in water. A. sulphuric acid and manganese dioxide B. powdered carbon and zinc chloride C. ammonium chloride and zinc chloride D. none of these
C. ammonium chloride and zinc chloride
Which of the following statements is NOT true regarding a cell?
A. The plates must be immersed in some electrolyte solution such as an acid, an alkali or a salt
B. Decreasing the distance between plates, decreases the internal resistance of the cell
C. The plates must be of different metals
D. Increasing the size of the electrodes, increases the emf of the cell
D. Increasing the size of the electrodes, increases the emf of the cell
The \_\_\_\_\_ rating of a circuit breaker is the maximum short circuit current which the breaker will interrupt safely. A. instantaneous B. interrupting capacity C. optimum current D. optimum voltage
B. interrupting capacity
A 2-pole ac generator is running at 1,500 rpm. What is the frequency? A. 25 Hz B. 50 Hz C. 60 Hz D. 45 Hz
A. 25 Hz
An ohmmeter measures A. very high power B. resistance C. insulation resistance D. temperature
B. resistance
If a transformer bank is using an open delta connection, how many single-phase transformers are interconnected? A. Only one B. Two C. Three D. More than three
B. Two
What is the advantage of star connection over mesh connection for the same phase voltage? A. It has a higher line voltage B. It has a higher line current C. It gives a higher apparent power D. All of these
A. It has a higher line voltage
A cell with an emf of 1.45 V is connected to an external resistance of 2 ohms. If the current drawn by the external resistance is 0.5 A, what is the internal resistance of the cell? A. 0.80 ohm B. 0.90 ohm C. 0.10 ohm D. 0.25 ohm
B. 0.90 ohm
Which of the following metals has the highest melting point? A. copper B. gold C. solver D. tungsten
B. gold
In an open delta connected system,
A. phase voltage is greater than line voltage
B. phase voltage is lesser than line voltage
C. phase voltage is equal to line voltage
D. phase voltage is zero
C. phase voltage is equal to line voltage
Electrical symbol represented by a broken line. A. Open wiring B. Circuit homerun C. Underground wiring D. Emergency wiring
A. Open wiring
Which of the following defines an insulator?
A. A substance that offers a low resistance to current flow
B. A substance that offers a high resistance to current flow
C. A form of a condenser
D. A substance that absorbs electricity
B. A substance that offers a high resistance to current flow
Among the multimeters, the \_\_\_\_\_ features compactness, simplicity and portability. A. VOM B. VOTM C. VTVM D. all of these
A. VOM
A squirrel cage induction motor has a \_\_\_\_\_ starting torque. A. very low B. zero C. very high D. moderate
A. very low
How many wattmeters are needed to measure unbalanced three-phase loads whose phase impedances cannot be opened? A. One B. Two C. Three D. Four
B. Two
The inert gas present in an incandescent bulb is primarily intended to
A. increase lumen output
B. activate the surface of the filament
C. decrease filament evaporation
D. reduce the hazards when the glass bulb is shattered
A. Increase lumen output
When a lead acid battery is in a nearly discharge condition, the electrolyte is in its \_\_\_\_\_ state. A. stable B. strongest C. weakest D. normal
C. weakest
A device used to measure the mechanical output of a motor or a generator is called A. watt-hour meter B. sphygmomanometer C. engine indicator D. dynamometer
D. dynamometer
Minimum oil circuit breakers are used for HV system. The oil is used to A. ensure effective operation B. prevent grounds C. cool the breaker D. quench the arc and as an insulator
D. quench the arc and as an insulator
Which of the following metals has the highest electrical and thermal conductivity? A. Gold B. Platinum C. Palladium D. Silver
D. Silver
When the speed of the alternator increases, the frequency A. varies exponentially B. remains the same C. increases D. decreases
C. increases
Which of the following is NOT a cause for a generator to vibrate? A. Misalignment B. Loose pigtails C. Loose bolts D. Faulty speed governor
B. Loose pigtails
An arc lamp takes 10 A at 50 V. Find the value of the resistance to be placed in series so that the lamps may burn correctly from 110-V supply. A. 5 ohms B. 11 ohms C. 6 ohms D. 10 ohms
C. 6 ohms
A 15-hp, 220 V shunt motor has an efficiency of 87% at full load. The resistance of the field is 440 ohms. What is the full load armature current? A. 67.59 A B. 57.96 A C. 75.69 A D. 49.58 A
B. 57.96 A
If a three-phase load is unbalanced, the most suitable system connection is a A. 3-wire star connection B. 3-wire closed delta connection C. 3-wire open delta connection D. 4-wire star connection
D. 4-wire star connection
The transformer oil used in a transformer provides A. insulation and cooling B. insulation, cooling and lubrication C. insulation and lubrication D. cooling and lubrication
A. insulation and cooling
An RME whose certificate of registration has been revoked may, after the lapse of \_\_\_\_\_ year(s) from the surrender thereof, be reissued with issued with such certificate upon approval by the Commission after he has established to the Board that he is still fit to continue practicing his profession. A. 3 B. 1 C. 2 D. 5
B. 1
What is the rated primary current of a 250 kVA, 480/230 - volt 3-phase transformer? A. 521 A B. 628 A C. 301 A D. 1086 A
C. 301 A
Mica is commonly used for \_\_\_\_\_. A. panelboards B. pole insulators C. appliance insulation D. commutator bar segments
D. commutator bar segments
Coulomb is to charge as a joule is to \_\_\_\_\_. A. heat B. emf C. energy D. power
C. energy
Which of the following instruments can be used to measure wire diameters? A. wire gauge B. Micrometer C. Megger D. Multitester
B. Micrometer