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 : 28.In a two winding transformer, the emf /turn in secondary winding is always......the induced emf power turn in primary A. equal to k times B. equal to 1/k times C. equal D. greater than
Last Answer : C. equal
Description : 6 In a two winding transformer, the primary and secondary induced emf E1 & E2 are always A. equal in magnitude B. anti phase with each other C. in phase with each other D. determined by load on transformer secondary
Last Answer : C. In phase with each other
Description : Ratio of voltages is inverse ratio of the A. transformer B. resistor C. iron core D. current
Last Answer : current
Description : During short circuit test iron losses are negligible because A. The current on secondary side is negligible B. The voltage on secondary side does not vary C. The voltage applied on primary side is low D. Full-load current is not supplied to the transformer
Last Answer : C) the voltage applied on primary side is low
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 : 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 : 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 : An iron cored inductance coil can be modelled, over a normal operating range of networks ,as A) non-Linear bilateral element B) linear bilateral element C) linear time varying element D) non-linear time invariant element
Last Answer : An iron cored inductance coil can be modelled, over a normal operating range of networks ,as linear bilateral element
Description : The effective resistance of an iron-cored choke working on ordinary supply frequency is more than its true resistance because of?
Last Answer : The effective resistance of an iron-cored choke working on ordinary supply frequency is more than its true resistance because of iron loss in core.
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 : What is the output current of a 480 Volt primary 208 volt secondary - 3 phase transformer?
Last Answer : You need to mention the Load connected to find the current.
Description : Which of the following statements identifies the difference between the primary windings and the secondary windings of a 2:1 stepdown transformer? A. The secondary windings have twice as much resistance ... primary windings. D. The secondary windings have half as many turns as the primary windings.
Last Answer : Answer: D
Description : A load with an impedance of 440 ohms is connected across the secondary of the transformer illustrated. If the input voltage is 110 VAC and the step-up ratio is 10 to 1, what will be the primary current? EL-0055 A. 2.5 amps B. 25 amps C. 250 amps D. current cannot be determined with information given
Last Answer : Answer: B
Description : A load is connected to the secondary of the transformer illustrated and the current through the load is 10 amps. If the step-up ratio is 10 to 1 and the input voltage is 110 VAC, what will be the current flow through the primary? EL-0055 A. 1 amp B. 10 amps C. 100 amps D. 1000 amps
Last Answer : Answer: C
Description : Which of the following statements is true concerning stepdown transformer operation? A. The inductance on the primary side is the same as the inductance on the secondary side. B. The voltage to the primary ... . D. The voltage to the primary side is greater than the voltage from the secondary side.
Description : Increasing the load to the secondary windings of a transformer will cause a/an ____________. A. decrease in the primary voltage B. increase in the primary voltage C. decrease in the primary current D. increase in the primary current
Description : If we give 2334 A, 540V on Primary side of 1.125 MVA step up transformer, then what will be the Secondary Current, If Secondary Voltage=11 KV?
Last Answer : A. As we know the Voltage & current relation for transformer-V1/V2 = I2/I1 We Know, VI= 540 V; V2=11KV or 11000 V; I1= 2334 Amps. By putting these value on Relation540/11000= I2/2334 So,I2 = 114.5 Amps
Description : What current flows in the transformer primary when its secondary is open?
Last Answer : A. When the secondary is open, there is no current in the secondary of the transformer. The primary takes a small current I0) from the source called no-load current which has a magnetizing ... ) producing the magnetic flux and a working component (I0 cosθ0) supplying real power for iron losses.
Last Answer : As we know the Voltage & current relation for transformer-V1/V2 = I2/I1 We Know, VI= 540 V; V2=11KV or 11000 V; I1= 2334 Amps. By putting these value on Relation540/11000= I2/2334 So,I2 = 114.5 Amps
Description : 29.In transformer terminology, the ratio 20:1 indicates that A. there are 20 turns on primary one turn on secondary B. secondary voltage is 1/20th of the primary C. primary current is 20 times greater than the secondary current D. for every 0 turns on primary, there is one turn on secondary
Last Answer : A. there are 20 turns on primary one turn on secondary
Description : A 1:5 step-up transformer has 120V across the primary and 600 ohms resistance across the secondary. Assuming 100% efficiency, the primary current equals (A) 0.2 Amp. (B) 5 Amps. (C) 10 Amps. (D) 20 Amps.
Last Answer : I1= V1 /R1 = 120/600 = 0.2 (η = 100%, losses are zero ∴V1 = VR = I1R1)
Description : A device used in an electrical circuit to change alternating current to direct current, is known as a _____________. A. current transformer B. rectifier C. condenser D. shunt
Description : The emf induced in the primary of a transformer (A) is in phase with the flux. (B) lags behind the flux by 90 degree. (C) leads the flux by 90 degree. (D) is in phase opposition to that of flux.
Last Answer : (C) leads the flux by 90 degree.
Description : The e.m.f. induced in the primary of a transformer: (A) is in phase with the flux (B) lags behind the flux by 90 degree (C) leads the flux by 90 degree (D) is in phase opposition to that of flux
Last Answer : The e.m.f. induced in the primary of a transformer: leads the flux by 90 degree
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 : 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 : 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 : 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 : when should I harvest red cored chantenay carrots
Last Answer : Need Answer
Description : The steel used in steel cored conductors is usually (a) alloy steel (b) stainless steel (c) mild steel (d) high speed steel (e) all of the above
Last Answer : (c) mild steel
Description : Which of the following materials is used for overhead transmission lines ? (a) Steel cored aluminium (b) Galvanised steel (c) Cadmium copper (d) Any of the above
Last Answer : (d) Any of the above
Description : The voltage induced across a certain coil is 200 mV. A 1200 resistor is connected to the coil terminals. The induced current will be: A. 1.7 mA B. 16 mA C. 12 mA D. 120 mA
Last Answer : The voltage induced across a certain coil is 200 mV. A 1200 resistor is connected to the coil terminals. The induced current will be: 1.7 mA
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 : Graph of alternating current is a A. cos wave B. tan wave C. curve D. sine wave
Last Answer : sine wave
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 : The induced current in transformer which produced in the direction perpendicular to flux, is known as: a. Conventional current b. electronic current c. Perpendicular current d. Eddy current
Last Answer : c. Perpendicular current
Description : In a transformer, with closed magnetic coupling between primary and secondary __ will improve: a) Efficiency b) All day efficiency c) Regulation d) None of the above
Last Answer : Ans: C
Description : When a low input voltage is imparted to a device which then delivers a high output voltage, the device is known as a _____________. A. primary transformer B. secondary transformer C. stepdown transformer D. stepup transformer
Description : Relative to the secondary winding of a step-up transformer, the primary winding will have _____________. A. more turns B. fewer turns C. half as many turns D. twice as many turns
Description : When a transformer is used to step down voltage, the low voltage winding is _____________. A. part of the core B. the primary coil C. not insulated D. the secondary coil
Description : If a transformer is connected to a DC source, the transformer will overload at the ____________. A. contacts B. primary coil C. secondary coil D. core