For an electron, the journey from terminal to terminal is not a direct route. a)Resistivity of Cu and Al is low(act as a good conductor). Resistance of a conductor also depends upon nature of material of conductor,temperature of conductor. A conductor has large number of free electrons.When a potential difference is maintained across the ends of conductor,the free electrons move from one end to other end.During their movement,they collide with each other and with atoms of conductor.These collision opposes the movement of electrons  from one end to other end.This opposition to the flow of electrons due to collision is the resistance.More the collision suffered by electron in a conductor,more is the resistance. A variable resistor has a resistance that can be changed. Variable definition, apt or liable to vary or change; changeable: variable weather;variable moods. Example: Analyzing a more complex resistor circuit. Resistance training is based on the principle that muscles of the body will work to overcome a resistance force when they are required to do so. Flow of electrons in a conductor is electric current. S.I. Definition of Variable Resistor It is an electronic component. Silver is the best conductor of electricity. Thus, ratio of resistance before stretching to resistance after stretching can be given as follows: Thus, resistance increases four times after stretching of wire. As current is passed through the metal element in this kettle, resistance causes the metal to get hot and so boils the water. Many domestic appliances use resistance to transfer electrical energy to heat and light energy. When a variable resistor is used as a potential divider by using 3 … Resistance is the hindrance to the flow of charge. Rheostat: This is a device which is used in a circuit to provide variable resistance. The goal of audio amplifiers is to reproduce input audio signals at sound-producing output elements, with desired volume and power levels—faithfully, efficiently, and at low distortion. 1) Connecting wires in electric circuit are made up of Cu and Al. Component that is used to resist the flow of electric current in a circuit is called resistor. Work your outer thighs as you perform this lateral slide movement. 4) Insulators are used to protect ourselves from severe shock of electric current. The classification of this can be done based on two important parameters like Resistance (R-ohms) & Power rating (P-Watts). Resistors are joined in the circuit in two different methods, i.e., in series and in parallel. This variable resistance makes resistance bands particularly nice for beginners, those rehabbing from an injury, or who are learning a new exercise and are perfecting form. or own an. flow of electrons through them. Academic Partner . Your email address will not be published. (b) Establish the relationship between 1 kWh and SI unit of energy. A meter-long piece of large-diameter copper wire may have a resistance of 10 −5 Ω, and superconductors have no resistance at all (they are non-ohmic). Contact us on below numbers. While some other materials create more hindrance in the flow of electric current, i.e. So, new resistance is (1/16)th of original resistance. Stand on the center of a resistance band and hold the ends in each hand, pulling the band taut. A variable resistor is a resistor of which the electric resistance value can be adjusted. Resistivity, commonly symbolized by the Greek letter rho, ρ, is quantitatively equal to the resistance R of a specimen such as a wire, multiplied by its cross-sectional area A, and divided by its length l; ρ = RA/l.The unit of resistance is the ohm.In the metre-kilogram-second (mks) system, the ratio of area in square metres to length in metres simplifies to just metres. 1800-212-7858 / 9372462318. Solving a circuit with series and parallel resistors . Solution: Given, Resistivity (ρ) = 10 x 10−8 Ω m, Length ( l ) = 2 m, Diameter = 0.3 mm, Now, Radius of wire `= text(Diameter)/(2) = (0.3 mm) / (2) = 0.15 mm = 1.5 xx 10^-5 m`, Or, `R=(10xx10^-8Ω\xx2m)/(7.65xx10^-9m^2)`.