what is the principle behind the coooling of AC?
361464
the principle is by compressing a coolant, and injecting this coolant into a small pipe, the size will minimize heat built up, as the coolant moves around the pipe or coil, air is blow into this coil which result into cooler air.\n\nThe coolant is then compress back to repeat the process.
994448
It takes energy to evaporate.  When a liquid reaches the evaporation point, an amount of the liquid starts to turn to a gas, to complete this transformation in state, it absorbs energy from the surrounding liquid which cools it.\n\nYour Air Conditioner works on the same principle.  In your attic is a coil where high pressure refridgerant is suddenly exposed to a low pressure zone inside the coil of your air conditioner.  When it meets this low pressure zone, it evaporates from a liquid to a gas.  Again, to make this state change, it absorbs energy from anything around it, in this case the air flowing over the coils provides that energy.\n\nThe gas then is pushed through the system out to your outside unit where the excess heat it absorbed is vented off and the gas is compressed back into a liquid.
649873
in electroplating, the metal ions would discharge at the cathode, ie negative electrode since they are positively charged. for continuous plating you need to maintain your object-to-be-plated as the negative electrode. A DC source maintains a constant potential and hence it is used. An AC source alternates between a +ve and a -ve value many times in one second. as a result, your electrodes would never have a fixed charge and the metal ions would be attracted alternately by one electrode and then the other around 50 times in a sec---the result being they would go nowhere and your object would never get plated.
414551
The power factor of an AC electric power system is defined as the ratio of the real power to the apparent power.\n\nExplanation\n\nIn a purely resistive AC circuit, voltage and current waveforms are in step, changing polarity at the same instant in each cycle. Where reactive loads are present, such as capacitors or inductors, energy storage in the loads result in a time difference between the current and voltage waveforms. Since this stored energy returns to the source and is not available to do work at the load, a circuit with a low power factor will have higher currents to transfer a given quantity of power than a circuit with a high power factor.\n\nReal power is the capacity of the circuit for performing work in a particular time. Due to reactive elements of the load, the apparent power, which is the product of the voltage and current in the circuit, will be equal to or greater than the real power. The reactive power is a measure of the stored energy that is reflected to the source during each alternating current cycle.\n\nAC power flow has the three components: real power (P), measured in watts (W); apparent power (S), measured in volt-amperes (VA); and reactive power (Q), measured in reactive volt-amperes (VAr).\n\nThe power factor can be expressed as:\nP/S\nIn the case of a perfectly sinusoidal waveform, P, Q and S can be expressed as vectors that form a vector triangle such that:\nS*S=P*P+Q*Q\n\nBy definition, the power factor is a dimensionless number between 0 and 1. When power factor is equal to 0, the energy flow is entirely reactive, and stored energy in the load returns to the source on each cycle. When the power factor is 1, all the energy supplied by the source is consumed by the load. Power factors are usually stated as "leading" or "lagging" to show the sign of the phase angle.\n\nThe power factor is determined by the type of loads connected to the power system. These can be\n\nResistive \nInductive \nCapacitive \nIf a purely resistive load is connected to a power supply, current and voltage will change polarity in phase, the power factor will be unity (1), and the electrical energy flows in a single direction across the network in each cycle. Inductive loads such as transformers and motors (any type of wound coil) generate reactive power with current waveform lagging the voltage. Capacitive loads such as capacitor banks or buried cable generate reactive power with current phase leading the voltage. Both types of loads will absorb energy during part of the AC cycle, only to send this energy back to the source during the rest of the cycle.\n\nFor example, to get 1 kW of real power if the power factor is unity, 1 kVA of apparent power needs to be transferred (1 kVA = 1 kW × 1). At low values of power factor, more apparent power needs to be transferred to get the same real power. To get 1 kW of real power at 0.2 power factor 5 kVA of apparent power needs to be transferred (1 kW = 5 kVA × 0.2).\n\nIt is often possible to adjust the power factor of a system to very near unity. This practice is known as power factor correction and is achieved by switching in or out banks of inductors or capacitors. For example the inductive effect of motor loads may be offset by locally connected capacitors.\n\nEnergy losses in transmission lines increase with increasing current. Where a load has a power factor lower than 1, more current is required to deliver the same amount of useful energy. Power companies therefore require that customers, especially those with large loads, maintain the power factors of their respective loads within specified limits or be subject to additional charges. Engineers are often interested in the power factor of a load as one of the factors that affect the efficiency of power transmission.\n\n\nNon-sinusoidal components\n\n\nIn circuits having only sinusoidal currents and voltages, the power factor effect arises only from the difference in phase between the current and voltage. Th
604716
Need to know a need or application. AC voltage by definition is bipolar. What are you trying to do?
290511
As a train runs, it is in contact with the overhead power cables. The train draws power and runs direct current motors, which in are coupled to the wheels. The wheels turn and the train runs. These trains also have regenerative braking systems where the energy lost during braking is recovered and are stored. This energy can then be supplied back to the overhead cables, when required.\n\nRecent advances use alternating current motors to run the train. The voltage is much higher in a.c. and is hence more energy efficient.
137274
By definition, it's accelleration.
52317
Can't really remember, but one of them is the CFC in air conditioners
977140
DC Current flows through a long wire around ferrous core ,this establishes a magnetic field but is only half the function. If u substitute AC current it will magnetize and the field will fluctuate. Now if u rap some more wire around the AC exp. u will find that there will be current transformed across to the secondary winding with an turns ratio between the 2 coils with no physical connection.
577456
basically all things tend to have minimum potential energy. this can be achieved when the charges stay as far away as possible from each other. \n\nhence when charges are given to a conductor the are distributed uniformly,as in the case of a symmetrical conductor, on the outer surface of the conductor to minimise potential energy. \n\nif the conductor is asymmetrical, then the charge distribution is inversely proportional to the radius of curvature.
76334
In alternating current circuits, energy storage elements such as inductance and capacitance may result in periodic reversals of the direction of energy flow. The portion of power flow that, averaged over a complete cycle of the AC waveform, results in net transfer of energy in one direction is known as real power. That portion of power flow due to stored energy, that returns to the source in each cycle, is known as reactive power.
1139671
Is he stupid?  Please show him this question and all the answers saying he an idiot.  Air conditioners run based on how hot it is inside the building and if you are constantly letting more heat into your building, the air conditioner will keep running.  Not only is that a huge waste of money, but it also doesn't effectively cool the building.
770615
It's because when air gets hot it expands, and when it gets cold it contracts.  The cold air coming from the air conditioner is denser than the air that's already in the house, so it tends to sink.  If the AC vent were in the floor, the air higher up would never get cold, but with the vent in the ceiling, the cold air falls through the room and cools everything.  In the same manner, hot air rises, so having the vents in the floor makes the hot air float through the room instead of just staying on the ceiling and leaving the floor cold.
800315
visit\nhttp://www.allaboutcircuits.com/vol_3/chpt_7/5.html
295258
There is a tried-and-true analogy that teachers love to use, and that is to think of electricity as water. When you do, you get these parallels:\nA pipe = a piece of wire\nAn open valve = a closed switch (and vice versa)\nPressure = voltage\nVolume = charge\nFlow rate = current\nA restriction in a pipe = resistance\nA container = capacitance\nA long smooth pipe = an inductance\nA one-way valve = a diode\nThese analogies help you understand the behavior of electricity. For instance:\nAs you fill a container with water the pressure goes up\nAs you fill a capacitor with charge the voltage goes up\nThe flow through a restriction increases if you enlarge the restriction or increase the pressure\nThe current in a resistor increases if you reduce the resistance or increase the voltage\nIf you suddenly stop the water flow in a long smooth pipe there will be a pressure spike\nIf you suddunly interrupt the current in an inductor there will be a voltage spike\n\nI hope you can carry on from there.
389562
Well that book must have a misprint or something because q=CV is not accurate. Actually if the potential of a outside conductor depends on the size, then this is a variable dependent, (and therefore mutable) in structure, shape, and amount of conduction based on the charge of q. For if C=q/v, then the isolated conductor's potential to change will be hinder and therefore not fully capable of allowing a full transformation for V due to the charge (power) of q.
331591
I heard that AC interferes with your nervous system causing your muscles to clench, making it impossible for you to let go of whatever is electrocuting you. DC doesn't, so you can let go as soon as you feel the shock.