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What is the power when a voltage of 120V drives a 2-A current through a device?
Wiki User
∙ 9y ago
Power is volts time amps, so 120 V time 2 A = 240 W. That is, of course, assuming that the voltage is DC, or the load is purely resistive. If there is any capacitive or inductive reactance in the device, and the voltage is AC, the true power will not be equal to the apparent power because of a phenomenon called power factor due to phase angle of voltage not being equal to current.
Wiki User
∙ 13y ago
Wiki User
∙ 9y agothe answer is 120 x 2 watts.
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What colour code for 3 pin plug in NZ?
The live wire is brown in coulor while the earth wireis green and yellow in color and neutral wire is blue in colour. Uses of these three wire: Live wire:It's connected with fuse.It carries a voltage which drives electric current through the electrical appliances. Earth wire:It is a safety device and protect us from electric shock. Neutral wire:It offers a return path by electric current.
When current transformer is overloaded?
when your current transformer is over loaded make sure it turns back into a car and drives away
What is induction and conduction?
Induction means "induced current." An inductor (like a coil) drives the current from it's own magnetic fields when a voltage source is applied to either end of the coil. Another way current is induced is when a current in one wire creates a magnetic field which can "induce" current in another wire that is parallel to the first wire.Conduction just means that a material has electrical properties that allow current to flow such as copper or other conductive metals. Usually denoted in math as a lower case Greek symbol sigma.CommentCurrents are not induced. Voltages are induced.
What is a stand by current?
Standby current is the current that a device draws when it is not actively performing its function. This current would be measured in amperage, and commonly amperes, milliamperes or microamperes would be the units of measurement. As an example of a device drawing standby current; a radio transmitter may not be actively transmitting, but the power supply is turned on, and the transmitter is ready to operate. In this case, the transmitter is drawing very little power. A computer can be in standby mode and drawing "standby current" , examples of which are also "hibernation" and "sleep" modes. The computer display and hard disk drives are turned off, and the CPU is throttled down to low power state. However, memory is kept active, which requires just a small amount of battery power.
Why does the national grid use different voltages?
When transferring power over distance, the designer of the power line selects a voltage that optimizes the amount of power that is transferred, ie, minimizes the amount of power that is lost. There are tradeoffs in the selection of a voltage for a transmission line, as there are in almost any aspect of design. Too low a voltage (which requires a higher current) results in increased resistive losses in the lines, or you have to use heaver wire, which increases costs, not just of the wire, but of the stronger towers needed to support the wire. Too high a voltage leads to corona discharge losses and losses due to capacitance between lines and lines to ground. In addition, an AC voltage can be easily changed from one voltage to another with very small loss in power. So bottom line, each distribution line has a voltage selected to be optimum for that line. Connections between lines of different voltages are easily done via transformers.wire has inherent resistance. Power lost in this resistance is equivalent to P = I*I*R, where I is the current. Reducing the amount of current will reduce the inherent losses due to transporting power long distances. Power is equivalent to P = V*I; So, if we reduce the current, we must increase the voltage to maintain the same amount of power.Simply put, it is much more efficient. There is less loss transmitting the same amount of power down a line using high voltage rather than a lower voltage. Let's look and see why. Consider that the transmission lines have resistive properties (in ohms/foot). These represent a fixed loss; we can't get around them. We start with Ohm's Law: V=IR, and the definition of Power: P=VI. Substituting IR for V, we see that P=I²R. What this tells us is that the amount of power lost in the lines is equal to the square of the current flowing through the lines, times the resistance of the lines. The amount of power transmitted is constant, and the resistance in the lines is constant. So, if we double the voltage, the current is cut in half, and the losses are cut in quarter. The simple mathematics drives (dictates) that we use as high a voltage as is practical to transmit power over long lines to minimize the loss.
What is the value of a resistance if 20v drives 2a through it?
Simply divide the voltage by the current. This means you apply Ohm's Law.
What must voltage be?
Voltage is a measure of the E.M.F (electromotive force) which drives current around a circuit.
What type of input device uses the principle of magnetic induction to produce a voltage signal?
Hard Drives Floppy Drives Tape Drives Drum Drives
What is more is correct v is proportional to i or i is proportional to v?
The induced current is proportional to applied voltage. i is proportional to v Or you might say, "A current source drives a fixed current through a circuit. Then the voltage developed is proportional to i" . Both forms are equally correct. Voltage sources are more common than current sources so the first form is more common.
What is the meaning of 'voltage drives current'?
Think of Voltage as the pressure and Amperage (current) as flow. If you think of it as pipes with water then the pressure would be voltage, and current would be how much water flows past a certain point in the pipe in a given time.
In an electric circuit what provides the push?
You could consider the Voltage as the pushing force in a circuit. It drives the current.
What is voltage?
A type of "pressure" that drives electrical charges through a circuit. Voltage is how the electric potential energy differences are measured.
Whether high impedance drives the currecnt or voltage more?
No, This will act in reverse.Note: This will act only for alternating current and there will be no effect on direct current.
How connecting an electric device to a battery produces a current in the device.?
If we connect a battery to a device and complete a circuit, current will flow in that circuit and through the device. A battery (in good condition) is an electrical storage device. Most of the ones we are familiar with are chemical cells. There are chemicals inside that would like to react, but cannot unless there is an external circuit through which electrons can move to get from one electrode in the battery to the other. The potential chemical energy in a battery can be converted into electrical energy by completing that circuit. There is a force called voltagethat arises between the electrodes of the battery. And this voltage (electromotive force, or EMF) is the way that the chemical potential energy expresses itself. Because the battery can convert chemical potential energy into electricity owing to that EMF between the electrodes, connecting a circuit across the battery will allow current to flow as the chemical reactions in the battery proceed. A very rough analogy can be drawn by looking at gravitational potential energy. If a Bowling ball is sitting on the floor and it is lifted onto a table, its gravitational potential energy has been increased. This is distantly similar to the chemical reactions that want to occur in the battery; they are potential energy, too. If the bowling ball rolls off the edge of the table, the potential energy is converted into kinetic energy by gravity. When we hook up an external circuit to the battery, the chemical potential energy (expressed as voltage) drives electrical current through that circuit and the device in it. The circuit here is composed of conductors and the device. Electrons in the conductors are hanging around in the conduction band, and if a voltage is applied, those electrons will begin moving in response. The device must be conductive to some extent, and it, too, will have this electron current flowing through it. The battery has been connected to a circuit and drives current through that circuit. The chemical potential energy in the battery is converted into electrical energy in the circuit and the device connected to it.
How does connecting an electric device to a battery produce an current in the device?
If we connect a battery to a device and complete a circuit, current will flow in that circuit and through the device. A battery (in good condition) is an electrical storage device. Most of the ones we are familiar with are chemical cells. There are chemicals inside that would like to react, but cannot unless there is an external circuit through which electrons can move to get from one electrode in the battery to the other. The potential chemical energy in a battery can be converted into electrical energy by completing that circuit. There is a force called voltagethat arises between the electrodes of the battery. And this voltage (electromotive force, or EMF) is the way that the chemical potential energy expresses itself. Because the battery can convert chemical potential energy into electricity owing to that EMF between the electrodes, connecting a circuit across the battery will allow current to flow as the chemical reactions in the battery proceed. A very rough analogy can be drawn by looking at gravitational potential energy. If a bowling ball is sitting on the floor and it is lifted onto a table, its gravitational potential energy has been increased. This is distantly similar to the chemical reactions that want to occur in the battery; they are potential energy, too. If the bowling ball rolls off the edge of the table, the potential energy is converted into kinetic energy by gravity. When we hook up an external circuit to the battery, the chemical potential energy (expressed as voltage) drives electrical current through that circuit and the device in it. The circuit here is composed of conductors and the device. Electrons in the conductors are hanging around in the conduction band, and if a voltage is applied, those electrons will begin moving in response. The device must be conductive to some extent, and it, too, will have this electron current flowing through it. The battery has been connected to a circuit and drives current through that circuit. The chemical potential energy in the battery is converted into electrical energy in the circuit and the device connected to it.
How voltage become zero in centre point?
If you have an alternating current, which changes direction, and we graph the direction in terms of positive and negative, then at some point, as the current changes from positive to negative, and from negative to positive, it must pass through zero. If you imagine a car, driving forwards, that then changes direction and drives in reverse, there must be a point when it is not moving. Changes of direction, or voltage, are not instantaneous.
What is the driving force which causes electrons to flow through conductors?
Voltage is responsible to flow the current in a circuit. Voltage is also known as potential difference or electric pressure. When there is a potential difference across a conductive circuit current starts flow from the higher potential to lower potential.
