Description : Ratio of voltages is equal to ratio of A. iron sheets in core B. coil C. number of turns in coil D. all of above
Last Answer : number of turns in coil
Description : In transformer, alternating current is induced inA. primary coil B. secondary coil C. iron core D. resistor
Last Answer : primary coil
Description : Which of the following statements concerning a simple parallel resistance circuit is correct? A. The voltage drop across each resistor is the same. B. The total current flow equals the reciprocal ... resistances. D. The total voltage equals the sum of the individual voltages across each resistance.
Last Answer : Answer: A
Description : In transformer, the core is made up of soft iron in order to pass the maximum A. flux B. current C. magnetic flux D. voltage
Last Answer : magnetic flux
Description : A transformer has a turns ratio of two to one. If a 100 ohm resistor is connected on the high side, its resistance as measured on the low side would be: w) 25 ohms x) 50 ohms y) 100 ohms z) 400 ohms
Last Answer : ANSWER: W -- 25 OHMS
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
Last Answer : Answer: D
Description : A component that allows only unidirectional current to pass through it is A. resistor B. inductor C. transformer D. diode
Last Answer : diode
Description : An AC supply of 230 V is applied to half wave rectifier circuit. A transformer turns ratio is 20 : 1. Find i) Output DC voltage (ii) Peak Inverse Voltage (PIV)
Last Answer : Solution:
Description : When troubleshooting a console circuit card suspected of being faulty, first check operating voltages, clean the card and then _________________. A. make sure wired connections and push-on connectors ... circuit traces with an ohmmeter D. measure the gain of each transistor or integrated circuit
Description : The best material for the core of a transformer is – (1) stainless steel (2) mild steel (3) hard steel (4) soft iron
Last Answer : (4) soft iron Explanation: Iron has a very large magnetic response: it greatly amplifies an applied magnetic field. The transformer's ability to transfer energy depends on the strength of the magnetic ... field is amplified. The input energy can then be lower while still having the same effect.
Description : The best material for the core of a transformer is (1) stainless steel (2) mild steel (3) hard steel (4) soft iron
Last Answer : soft iron
Description : The inverse definite mean time relays are used for over current and earth fault protection of transformer against (a) heavy loads (b) internal short-circuits (c) external short-circuits (d) all of the above
Last Answer : (b) internal short-circuits
Last Answer : The inverse definite mean time relays are used for over current and earth fault protection of transformer against internal short-circuits.
Description : Draw the symbol of i) Iron core inductor ii) variable capacitor iii) resistor iv) Ferrite core inductor
Last Answer : Iron core inductor: Ferrite core inductor:
Description : 43 The purpose of providing an iron core in a transformer is to A.Provide support to windings B. Reduce hysteresis loss C. decrease the reluctance of the magnetic path D. reduce eddy current losses
Last Answer : C. Decrease the reluctance of the magnetic path
Description : When secondary of a current transformer is open-circuited its iron core will be?
Last Answer : When secondary of a current transformer is open-circuited its iron core will be hot because of heavy iron losses taking place in it due to high flux density.
Description : 19 Transformer cores are built up from laminations rather than from solid metal so that A. Oil penetrates the core more easily B. Eddy current loss is reduced C. Less lamination is required for the windings D. Turn ratio is higher than voltage ratio
Last Answer : B. Eddy current loss is reduced
Description : The following is an amplifying device : (1) a transformer (2) a transistor (3) a diode (4) a resistor
Last Answer : (2) a transistor Explanation: A transistor is a semiconductor device used to amplify or switch electronic signals and electrical power.
Description : The component used for tuning a radio is basically a variable – (1) Resistor (2) Condenser (3) Inductor (4) Transformer
Last Answer : (2) Condenser Explanation: A tuning capacitor or tuning condenser is a variable capacitor used in an electronic circuit of a radio. It usually connects in parallel to a loop antenna and its capacitance may be intentionally and repeatedly changed mechanically or electronically.
Description : The 'Choke' used with a tube light is basically – (1) an inductor (2) a capacitor (3) a transformer (4) a resistor
Last Answer : (1) an inductor Explanation: In electronics, a choke is an inductor used to block higher-frequency alternating current (AC) in an electrical circuit, while passing lower-frequency or direct ... created by suddenly interrupting the current in choke, which is connected in series with the tubelight.
Description : The component used for tuning a radio is basically a variable (1) Resistor (2) Condenser (3) Inductor (4) Transformer
Last Answer : Condenser
Description : The ‘Choke’ used with a tube light is basically (1) an inductor (2) a capacitor (3) a transformer (4) a resistor
Last Answer : an inductor
Description : High voltages lead to A. less power loss B. more power loss C. high current D. high resistance
Last Answer : less power loss
Description : Define following parameter of rectifier: (i) Ripple factor (ii) Efficiency (iii) Peak Inverse Voltage (iv) Transformer utilization factor
Last Answer : (i) Ripple Factor - Ripple factor (γ) may be defined as the ratio of the root mean square (rms) value of the ripple voltage to the absolute value of the DC component of the ... the same rectifier. Effective VA Rating of transformer is the average of primary and secondary VA rating of transformer.
Description : Which of the following iron core electromagnets creates the greatest amount of magnetic flux: w) 1,000 coils, 2 amps of current x) 250 coils, 7 amps of current y) 700 coils, 3 amps of current
Last Answer : ANSWER: Y -- 700 COILS, 3 AMPS OF CURRENT
Description : In replacing a defective transformer with a new one, which of the following actions must be carried out to insure proper operation of the equipment it serves? A. The secondary leads must be grounded ... magnetize it. D. The iron core must be grounded for 10 minutes to remove any residual magnetism.
Last Answer : Answer: B
Description : [53] The iron loss of the transformer is negligible during short circuit test because A. The entire input is just sufficient to meet Cu losses only B. Flux produced is a small fraction of the normal flux C. Iron core becomes fully saturated D. Supply frequency is held constant
Last Answer : B. Flux produced is a small fraction of the normal flux
Description : 46 The core used in high frequency transformer is usually A. Copper core B. Cost iron core C. Air core D.Mid steel core
Last Answer : C. Air core
Last Answer : The purpose of providing an iron core in a transformer is to decrease the reluctance of the magnetic path.
Last Answer : The purpose of providing iron core in a step-up transformer is to decrease the magnitude of magnetizing current.
Description : What is the core of the transformer made of ?
Last Answer : The core of the transformer is made of: The core of the transformer is usually made of a type of steel called silicon steel. Transformer cores are not usually made of normal stainless steel.
Description : Of which irom is Core of transformer made up?
Last Answer : – Soft iron
Description : The hook-on AC volt-ammeter consists essentially of a split-core and a rectifiertype instrument connected to the secondary winding of a _____________. A. potential transformer B. control transformer C. current transformer D. reactance transformer
Last Answer : Answer: C
Description : For V/F control, when frequency is increased in transformer a) Core loss component current increases, Magnetizing component current decreases b) Core loss component current increases, ... component current decreases d) Core loss component current decreases, Magnetizing component current increases
Last Answer : Ans: Core loss component current decreases, Magnetizing component current decreases
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 : 8 The transformer core is laminated to A. Reduce the copper losses B. Reduce the core losses C. Reduce the eddy current losses D. None of the above
Last Answer : C. Reduce the eddy current losses
Description : If a current of 1.5 A is maintained in a resistor of 10 2, then the energy dissipated in the resistor in 1 minute will be : (1) 15 W (2) 22.5 W (3) 135 W (4) 1350 W
Last Answer : (4) 1350 W Explanation: The potential difference or voltage, V, across two points is defined as the energy, E dissipated or transferred by a coulomb of charge 9, that moves through two points.
Description : Current through each resistor when they are connected in series is A. different B. same C. can be both A and B D. decreasing
Last Answer : same
Description : If current of 20 mA is passing through op-amp and voltage drop across series resistor is 10 V then value of resistance is A. 500Ω B. 400Ω C. 300Ω D. 200Ω
Last Answer : 500Ω
Description : To limit current in LED, resistor should be connected in A. parallel B. series C. evacuated flask D. ionized tube
Last Answer : series
Description : A current of 5 amps passes through a 10 ohm resistor. What power is dissipated by this resistor under these conditions?
Last Answer : ANSWER: 250 WATTS
Description : The potential difference across a 4 ohm resistor is 20 volts. What is the current in the resistor?
Last Answer : ANSWER: 5 AMPS
Description : A current of 6 amperes flows through a 2 ohm resistor for 30 seconds. How many coulombs of charge have passed through the resistor?
Last Answer : ANSWER: 180 COULOMBS
Description : A resistor of value R/2 is connected in parallel with a resistor of value R/3. The voltage drop across the parallel combination is V. The total current supplied by the voltage source is: w) 2 V/R (read: 2 V over R) x) 3 V/R (read: 3 V over R) y) 4 V/R (read: 4 V over R) z) 5 V/R (read: 5 V over R)
Last Answer : ANSWER: Z -- 5 V/R
Description : A series circuit consists of a two ohm RESISTOR and a one ohm INDUCTOR. The relationship between current and voltage is: w) current will lag by 30 degrees. x) current will lag by 26 degrees. y) current will lead by 26 degrees. z) current will lead by 30 degrees.
Last Answer : ANSWER: X -- CURRENT WILL LAG BY 26 DEGREES.
Description : A 10 ohm and a 20 ohm resistor are connected in parallel to a current source. What fraction of the current flows through the 20 ohm resistor? w) 1/2 x) 1/3 y) 2/3 z) 3/4
Last Answer : ANSWER: X -- 1/3
Description : An LED is operated on a 12 volt automobile circuit. The voltage drop across the LED is 2 volts and the current must be limited to 50 milliamps to prevent its overheating and destruction. What size resistor must be used? w) 60 ohms x) 100 ohms y) 120 ohms z) 200 ohms
Last Answer : ANSWER: Z -- 200 OHMS
Description : A 20 ohm resistor and a 60 ohm resistor are connected in parallel to a voltage source. If the current in the 60 ohm resistor is one ampere, the current in the 20 ohm resistor will be: w) 1/3 ampere x) 2/3 ampere y) 1 ampere z) 3 amperes
Last Answer : ANSWER: Z -- 3 AMPERES
Description : A current of 5 amps passes through a 10 ohm resistor. How many joules of energy will be generated by this resistor in 2 seconds?
Last Answer : ANSWER: 500 JOULES
Description : Two transformers of identical voltages but different capacities are operated in parallel, for satisfactory load sharing: a) Impedances should be equal b) Per unit impedance must be equal c) per unit impedance and X/R ratio must be equal d) Impedance and X/R ratio must be equal
Last Answer : Ans: C