Description : Why inductor current lags inductor voltage ?
Answer :
Inductor is a wire wounding structure having a core material it induces emf which is opposite to the voltage supply and proportional to rate of change of current so current lags the voltage in inductor
asked
May 24, 2019
by
anonymous
Description : About trnsformer
Answer :
Acc to Ohms law V=IR but it is only applicable when our resistance R is constant, as in case of transformer we take impedence which is equivalent to resistance is not constant it varies with system parameters that why Ohms law not applicable in case of transformer
Description : What happens to the resistance when the current increases?
Answer :
Resistance reduces when current increases.
asked
Mar 15, 2018
by
anonymous
Description : The threshold frequency is the frequency below which : (1) photo current increases with voltage (2) photo current decreases with voltage (3) photo electric emission is not possible (4) photo current is constant
Answer :
photo electric emission is not possible
Description : Why does increase in current mean a decrease in voltage?
Answer :
This is because current flows from high potential to low potential to bring the two diffrent potential to unity , thus a reduced potential (voltage)
asked
Mar 10, 2018
by
anonymous
Description : The frequency of an alternating current is?
Answer :
The frequency of an alternating current is the number of waves passing through a point in one second.
asked
Mar 25, 2018
by
anonymous
Description : A network that consists of at least a voltage source or current source is called A) Active network B) Ideal network C) Sourced network D) Outsourced network
Answer :
A network that consists of at least a voltage source or current source is called Active network
asked
Apr 29, 2018
by
anonymous
Description : What happens when you reverse the direction of the current in an electromagnet?
Answer :
When you reverse current direction in an electromagnet, the magnetic poles will also change.
asked
Mar 14, 2018
by
anonymous
Description : A network is said to be under resonance when the voltage and the current at the network input terminals are (A) in phase (B) out of phase (C) in phase quadrature (D) in phase, and have equal magnitudes
Answer :
A network is said to be under resonance when the voltage and the current at the network input terminals are in phase
asked
Apr 28, 2018
by
anonymous
Answer :
In order that current should flow without causing excessive heating or voltage drop, the relay contacts should have low contact resistance, be clean and smooth, be of sufficient size and proper shape.
asked
Mar 19, 2018
by
anonymous
Description : When an alternating current passes through an ohmic resistance the electrical power converted into heat is?
Answer :
When an alternating current passes through an ohmic resistance the electrical power converted into heat is true power.
asked
Mar 25, 2018
by
anonymous
Description : Explain the characteristics of inductor to be considered while designing it. What is the effect of over current and increase in temperature on inductor.
asked
Mar 10, 2018
by
anonymous
Description : Explain why potential difference is necessary to produce current in a circuit.
asked
Jun 29, 2019
by
anonymous
Description : In a series R-C circuit, with the increase in frequency, current (A) Reduces (B) Increases (C) Does not change (D) Becomes zero
Answer :
In a series R-C circuit, with the increase in frequency, current Increases
asked
May 8, 2018
by
anonymous
Description : Why do we use AC current in our homes?
Answer :
We used it for cooking rice, For washing clothes and for lights in the house.
asked
Mar 11, 2018
by
anonymous
Description : why current flows in opposite direction of electrons?
Answer :
Hi team, the current flow is nothing but flow of electrons But the conventional direction I'd opposite to actual current flow . ..
asked
Oct 3, 2017
by
anonymous
Answer :
When a conductor carries more current on the surface as compared to core, it is due to skin effect.
asked
Mar 20, 2018
by
anonymous
Description : When current flows through heater coil it glows but supply wiring does not glow because?
Answer :
When current flows through heater coil it glows but supply wiring does not glow because resistance of heater coil is more than the supply wires.
asked
Mar 25, 2018
by
anonymous
Description : The internal resistances of an ideal current source, and an ideal voltage source are, respectively, (A) 0, ∞ (B) ∞, ∞ (C) ∞, 0 (D) 0,0
Answer :
The internal resistances of an ideal current source, and an ideal voltage source are, respectively, ∞, 0
asked
Apr 28, 2018
by
anonymous
Description : Why does induction motor have high starting current?
Answer :
In induction motor , the flux produce is quadrature to the applied voltage. Since when we are going to start motor , there is no flux present inside . So in order to lets say compensate it ... times of current to further increase flux. So that is reason for high starting current in induction motor
asked
Mar 15, 2018
by
anonymous
Description : Why does bleeding occur through the nose in high mountainous regions ? (1) The pressure of blood in capillaries is greater than the outside pressure (2) The pressure at high altitudes is greater than that on the plains (3) The blood pressure of a person increases at high altitudes (4) The blood pressure fluctuates and finally decreases drastically
Answer :
The blood pressure of a person increases at high altitudes
Description : When a person sitting on a swing stands up on the swing, the frequency of oscillation (1) decreases (2) increases (3) becomes infinite (4) does not change
Answer :
increases
Description : Which of the following is the least expensive protection for over current in low voltage system? (A) Rewireable fuse (B) Isolator (C) Oil Circuit breaker (D) Air break circuit breaker
Answer :
Which of the following is the least expensive protection for over current in low voltage system? (A) Rewireable fuse (B) Isolator (C) Oil Circuit breaker (D) Air break circuit breaker
Description : The eddy current loss in a dc generator is 400 W at 40 Hz frequency of reversal and constant flux density. When frequency is increased to 50 Hz., eddy current loss is : (A) 256 W (B) 320 W (C) 500 W (D) 625 W
Answer :
The eddy current loss in a dc generator is 400 W at 40 Hz frequency of reversal and constant flux density. When frequency is increased to 50 Hz., eddy current loss is : 625 W
asked
Apr 30, 2018
by
anonymous
Description : In a series RLC high Q circuit, the current peaks at a frequency (1) equal to the resonant frequency (2) greater than the resonant frequency (3) less than the resonant frequency (4) equal to half the resonant frequency
Answer :
In a series RLC high Q circuit, the current peaks at a frequency equal to the resonant frequency
asked
Apr 29, 2018
by
anonymous
Description : A current controlled voltage source is equivalent to : (A) series voltage feed -back amplifier (B) shunt current feed -back amplifier (C) shunt voltage feed -back amplifier (D) series current feed -back amplifier
Answer :
A current controlled voltage source is equivalent to : shunt voltage feed -back amplifier
asked
Apr 30, 2018
by
anonymous
Description : What kills, current or voltage?
Answer :
Current would kill. You can actually have thousands of bolts going through you and not even know it. Yes you probably know already voltage is current times resistance. Since your body is a resistor it would take just a small amount of current to create a very high voltage
asked
Aug 25, 2019
by
anonymous
Description : Explain lagging quantity and leading quantity, explain this concept with voltage and current waveform
Answer :
When two alternating quantities attain their respective zero or peak values simultaneously, the quantities are said to be in-phase quantities. When the quantities do not attain their respective zero or ... current is leading the voltage or the voltage is said to be lagging behind the current.
asked
Sep 7, 2018
by
anonymous
Description : Step-down transformer converts high voltage and low current into: (A) How voltage and high current (B) High voltage and low current (C) Low voltage and high current (D) None of the above
Answer :
Step-down transformer converts high voltage and low current into: Low voltage and high current
asked
May 8, 2018
by
anonymous
Description : Electrical shock happens for voltage/current?
Answer :
The severity ofelectric shockdepends on thecurrentflowing through the body, which is a function of the electromotive force (E) involts, and the contact resistance (R) in ohms.
asked
Oct 30, 2017
by
Niloy
Description : The initial rate of rise of current through a coil of inductance 10 H when suddenly connected to a D.C. supply of 200 V is_______Vs.
Answer :
The initial rate of rise of current through a coil of inductance 10 H when suddenly connected to a D.C. supply of 200 V is 20 Vs
asked
Mar 25, 2018
by
anonymous
Description : What happens when a current flows through a wire?
Answer :
Current can produce two effect one is heating effect and second is magnetic effect.
asked
Mar 14, 2018
by
anonymous
Description : List out any four effects of electric current used in measuring instruments & write name of meter working on it.
Answer :
Effects of Electric Current used in measuring instruments: 1. Magnetic Effect: PMMC and Moving Iron type Ammeters, voltmeter and Dynamometer type wattmeters etc. 2. Electromagnetic induction ... . Electrostatic effect: Voltmeters. 5. Hall Effect: Flux meter, Poynting vector wattmeter.
asked
Sep 6, 2018
by
anonymous
Description : Even at no-load, a transformer draws current from the mains. Why?
asked
Apr 28, 2020
by
anonymous
Answer :
In BJT there is movement of electrons and holes accros the junctions which is basicaly current flow.
asked
Sep 10, 2017
by
anonymous
Answer :
For measuring current at high frequency we should use thermocouple instrument.
asked
Mar 21, 2018
by
anonymous
Description : In the case of an unsymmetrical alternating current the average value must always be taken over?
Answer :
In the case of an unsymmetrical alternating current the average value must always be taken over the whole cycle.
asked
Mar 25, 2018
by
anonymous
Description : What is the direction of flow of electric current in an electric circuit?
Answer :
It flows from anode to cathode (direction of holes flow)
asked
Mar 14, 2018
by
anonymous
Description : 1. If the current in the core decreases, what will the strength of the magnetic field be? 2. What is the commonly used unit for measuring the speed of data transmission? 3. The Govt. of India does not provide any direct financial assistance to which scheme? 4. Why is fog common around Newfoundland coast? 5. ... has been reasonably satisfactory in connection? 19. Which river flows between the Vindhya and Satpura ranges? 20. Which was a journal brought out by Abul Kalam Azad ?
Answer :
Answer : 1. Decreases 2. Bits per second 3. Jeevan Sathi Yojana 4. Because warm and cold currents meet 5. Ranga II 6. Fatty tissue 7. Uttar Pradesh 8. Oil gas 9. Silvassa 10. Hunter 11. Sports ... 16. Speaker 17. Because of inadequate supply of air 18. Growth of GNP 19. Narmada 20. Al -Hilal
Description : In the induction type directional over current relay, when a short-circuit occurs in the circuit (A) power flows in reverse direction (B) power flows in normal direction (C) directional power element does not operate (D) over current element is not energized
Answer :
In the induction type directional over current relay, when a short-circuit occurs in the circuit power flows in reverse direction
asked
Apr 28, 2018
by
anonymous
Description : A linear network has a current input 4cos(ω t + 20º)A and a voltage output 10 cos(ωt +110º) V. Determine the associated impedance.
Answer :
Solution
asked
Apr 1, 2020
by
anonymous
Description : A zener voltage regulator has load requirements of 12 V and 2 A. The zener diode minimum current requirement is 0.2 A. The minimum voltage at input is 24 V. What is the required value of series resistance with source? A) 5.45 Ω B) 6 Ω C) 7.2 Ω D) 6.38 Ω
Answer :
A zener voltage regulator has load requirements of 12 V and 2 A. The zener diode minimum current requirement is 0.2 A. The minimum voltage at input is 24 V. What is the required value of series resistance with source? A) 5.45 Ω B) 6 Ω C) 7.2 Ω D) 6.38 Ω
asked
Jun 18, 2018
by
anonymous
Description : The inrush current of a transformer at no load is maximum if the supply voltage is switched on (1) at peak voltage value (2) at zero voltage value (3) at half voltage value (4) at 0.866 time voltage value
Answer :
At 0.866 time voltage value
asked
Apr 30, 2018
by
anonymous
Description : Which of the following theorems enables a number of voltage (or current) source to be combined directly into a single voltage (or current) source. (1) compensation theorem (2) reciprocity theorem (3) superposition theorem (4) Millman's theorem
Answer :
Which of the following theorems enables a number of voltage (or current) source to be combined directly into a single voltage (or current) source. (1) compensation theorem (2) reciprocity theorem (3) superposition theorem (4) Millman's theorem
asked
Apr 29, 2018
by
anonymous
Description : A ferrite core has less eddy current loss than an iron core because?
Answer :
A ferrite core has less eddy current loss than an iron core because ferrites have high hysteresis.
asked
Mar 25, 2018
by
anonymous
Description : The r.m.s. value of a sinusoidal A.C. current is equal to its value at an angle of______degrees.
Answer :
The r.m.s. value of a sinusoidal A.C. current is equal to its value at an angle of 45 degrees.
asked
Mar 24, 2018
by
anonymous
Description : Analyze the effect of supply voltage on performance of LED as regards current, Lumen output, efficacy and life.
Answer :
1) Effect on Current:- In LED current depends upon supply voltage, if voltage get changes then current also change but this change in current will be control by resistors which are connected in series. 2) ... 4) Effect on Life:- If supply voltage is not stable then life of LED get reduced.
asked
May 3, 2020
by
anonymous
Description : With the help of N-channel JFET describe the effect of input voltage VGS on output current ID.
Answer :
Working of N channel FET: * When a voltage is applied between the drain and source with a DC supply (VDD), the electrons flows from source to drain through narrow channel ... where the channel gets completely blocked and the drain current becomes zero is called pinch- off voltage.
asked
May 2, 2020
by
anonymous
Description : Define: i) Input Offset Voltage ii) Input offset Current iii) Input Bias Current iv) Output offset voltage
Answer :
Definition of parameters of OPAMP is follows: i) Input Offset Voltage: Input offset voltage is defined as the voltage that must be applied between the two input terminals of an OPAMP to null or ... to ground) and output voltage is obtained non zero such voltage is output offset voltage of opamp.
asked
May 2, 2020
by
anonymous
Answer :
Source transformation voltage source to current source and vice versa
asked
Mar 21, 2020
by
anonymous