2007-06-12 08:54:52 · 15 answers · asked by Anonymous in Science & Mathematics ➔ Engineering
I think that electricity can be more easily visualised if you imagine a water system instead.
Water flows through pipes, electricity flows through wires etc...
So electrical resistance is like the resistance water feels as it passes through the system. If there is a big pipe, lots of water can flow easily - there is little resistance, if it is a small pipe then not much water can flow because there is a lot of resistance to the water. If the water reaches a tap that is half open there is a resistance to stop the water flowing, the same with electrical components, these resist the electricity flow.
[technical bit here - Electrons carry the electric charge round the wires in a very simular way that water flows round the pipes hence the example]
Now where electricity encounters a rsistance - and all resistance, even wires do this, it looses energy and this is mostly lost as heat, so for example, an electric heater is really a wire coiled up that has lots of resistance, electricity flows along it, suffers the resistance and gives of heat
2007-06-12 11:47:54 · answer #1 · answered by whycantigetagoodnickname 7 · 0⤊ 0⤋
It is the resistance to the flow of electric charges. It is the inverse of electrical conductivity. It is a property of a material that tells you how easy or difficult it is to move electric current through the material. Metals like copper, gold, and silver are excellent conductors and have low electrical resistance. Materials like plastic, pure water, and rubber are poor conductors and have high electrical resistance.
Resistivity, which is a measure of how resistive a material is to electric current, can be easily found by using the formula:
R = r L/A where R is the total resistance, r is the resistivity, L is the length of the material, and A is the cross-sectional area of the material.
2007-06-12 09:02:42 · answer #2 · answered by msi_cord 7 · 0⤊ 0⤋
Electrical resistance exacts a voltage drop as the price for allowing electrical current to flow through the resistance. The use of the term resistance implies that the current flow will be in phase with the voltage across the resistor and that the current flow will be proportional to the voltage drop. These conditions are Ohm's Law. There are devices which do not meet these conditions. They can be useful, but they should be considered as another component class such as thermistors etc. Mathematically V = I x R, where V is the instantaneous voltage across the resistance, I is the instantaneous current through the resistance, and R is a constant specific for the resistance. If V is in Volts and I is in Amperes, then R will be in Ohms. Practical resistors vary modestly with temperature, but change very little with voltage or current, except as these change the temperature. A resistor should be the same for flow in either direction and for DC and AC of modest frequency. At high frequencies resistors can display inductance and/or capacitance. Resistors can be purchased with various resistance tolerances, with various temperature sensitivities, and with various power ratings. Running at full power rating may shorten life and may produce temperatures which affect adjacent components. Derating to 1/2 or even 1/3 power may be wise.
2016-05-18 03:08:32 · answer #3 · answered by mavis 3 · 0⤊ 0⤋
electrical resistance???? ITS CALLED NOT PAYING THE BIG BILL!!that drops on your door step..he.he......but could be the thickness of a wire or is...get the top nobs saying some silly bull..... and the current being sent through it....the thicker the cable the more power is sent through and less resistance ..thin cables get more resistance in flow....all you got to think about is a light bulb...its full of a gas ..but the wire is so thin... and if gets a power surge it will blow...and after time it will blow....and its the same as wires.. being changed on the National Grid pylons....they don't last for ever. as more houses more power needed...so pylons get upgrade with thicker cables..as can not conduct power at a greater rate....like a car or other things break down top speed 100mph...you take it over to 130mph..will not work for much longer..,,,,hope my words help you in some way if not all best .......if anyone thinks im wrong..let me no as need input....
2007-06-12 09:39:27 · answer #4 · answered by Tiggy want's a bit..... 4 · 0⤊ 0⤋
Electrical resistance is a measure of the degree to which an object opposes an electric current through it.
2007-06-12 09:00:06 · answer #5 · answered by ffordcash 5 · 0⤊ 1⤋
Resistance to the flow of electrical charge round a circuit. Some materials allow charge to move easily, some with difficulty and some not at all. Materials that allow easy movement of charge are called conductors - ones that do not allow movement are call insulators.
2007-06-12 09:02:32 · answer #6 · answered by mark_gordon_uk 1 · 0⤊ 0⤋
Electrical resistance is opposition of current within circuit and is measured in Ohms
2016-08-07 01:05:45 · answer #7 · answered by umair 1 · 0⤊ 0⤋
As I recall the definition from when I was in school it is "the opposition to the flow of electrical current". In fact, to show the difference between resistance and impedance it was stated that resistance is 'the opposition to the flow of direct current' while impedance is 'the opposition to the flow of alternating current'.
2007-06-12 09:18:46 · answer #8 · answered by EE dude 5 · 0⤊ 0⤋
It is anything that impedes the flow of electricity. Measured in ohms. The higher the ohm reading the greater the resistance.
2007-06-12 09:04:48 · answer #9 · answered by speedyb_67 2 · 0⤊ 0⤋
It's the Resistance to flow of electrons (current in Amps) within a circuit and is measured in 'Ohms'.
(Like a dam in a river will resist the flow (current) of water).
2007-06-13 06:02:41 · answer #10 · answered by Norrie 7 · 0⤊ 0⤋