Conductors: Materials that offer very little resistance where electrons can move easily. Examples: silver, copper, gold and aluminum. Insulators: Materials that present high resistance and restrict the flow of electrons. Examples: Rubber, paper, glass, wood and plastic.
What causes resistance in a circuit?
An electric current flows when electrons move through a conductor, such as a metal wire. The moving electrons can collide with the ions in the metal. This makes it more difficult for the current to flow, and causes resistance.
What is resistance and its formula?
Resistance has units of ohms (Ω), related to volts and amperes by 1 Ω = 1 V/A. There is a voltage or IR drop across a resistor, caused by the current flowing through it, given by V = IR.
Does an open circuit have resistance?
The resistance across an open circuit is equal to infinity. Open circuits are represented as a broken wire. For calculating an equivalent resistance, a resistor connected to the circuit at only one node is open.
Is voltage directly proportional to resistance?
Ohm’s law Equation tells us that the current in a circuit can be determined if the values of resistance and voltages are known. … Therefore, voltage is not proportional to resistance.
What are the three parts of electric circuit?
An electric circuit has three parts: An energy source – like a battery or mains power. An energy receiver – like a lightbulb. An energy pathway – like a wire.
What affects resistance in a wire?
The resistance of a wire is directly proportional to its length and inversely proportional to its cross-sectional area. Resistance also depends on the material of the conductor. … The resistance of a conductor, or circuit element, generally increases with increasing temperature.
What four things does the resistance of a wire depend on?
The resistance of a conductor depends on the cross sectional area of the conductor, the length of the conductor, and its resistivity. It is important to note that electrical conductivity and resistivity are inversely proportional, meaning that the more conductive something is the less resistive it is.
What is resistance and its unit?
Resistance is the hindrance offered by an object to the flow of current through it. Lower is the flow of current, higher is the resistance of a given material. SI unit of resistance is Ohm (Ω).
What is an example of resistance?
The act or an instance of resisting or the capacity to resist. Resistance is defined as a refusal to give in or to something that slows down or prevents something. An example of resistance is a child fighting against her kidnapper. An example of resistance is wind against the wings of a plane.