Question: What Causes Resistance?

What are the factors that affect resistance?

There are several factors that affect the resistance of a conductor;material, eg copper, has lower resistance than steel.length – longer wires have greater resistance.thickness – smaller diameter wires have greater resistance.temperature – heating a wire increases its resistance..

What are the 3 things resistance depends on?

Resistance depends on an object’s size, shape, and material. In Figure 3 below, the cylinder’s resistance is directly proportional to its length l. The longer the cylinder, the higher the resistance. Additionally, the resistance is inversely proportional to the cross sectional area A.

Why is resistance directly proportional to length?

As the length increases, the number of collisions by the moving free electrons with the fixed positive ions increases as more number of fixed positive ions are present in an increased length of the conductor. As a result, resistance increases.

How does length affect resistance?

First, the total length of the wires will affect the amount of resistance. The longer the wire, the more resistance that there will be. There is a direct relationship between the amount of resistance encountered by charge and the length of wire it must traverse. … Wider wires have a greater cross-sectional area.

What causes resistance in a metal?

In metal conductors, electrical current flows due to the exchange of electrons between atoms. As electrons move through a metal conductor, some collide with atoms, other electrons or impurities. These collisions cause resistance and generate heat.

Is voltage directly proportional to resistance?

In the first version of the formula, I = V/R, Ohm’s Law tells us that the electrical current in a circuit can be calculated by dividing the voltage by the resistance. In other words, the current is directly proportional to the voltage and inversely proportional to the resistance.

Does resistance increase when current increases?

The moving electrons can collide with the ions in the metal. This makes it more difficult for the current to flow, and causes resistance. … When resistance is increased in a circuit , for example by adding more electrical components , the current decreases as a result.

What would decrease the resistance of a wire?

Thicker wires have a larger cross-section that increases the surface area with which electrons can flow unimpeded. The thicker the wire, therefore, the lower the resistance.

Why is it better to use a cable with low resistance than high?

In most applications, a lower resistance means less power is converted to heat and lost to the surrounding environment and more of the supplied power gets to its intended destination. It also means that the wire and cable will run cooler and the power source can be smaller for a given load.

Does resistivity affect resistance?

Electrical Resistivity Thus the higher the resistivity value of ρ the more resistance and vice versa. … Then the factors which affect the resistance (R) of a conductor in ohms can be listed as: The resistivity (ρ) of the material from which the conductor is made. The total length (L) of the conductor.

What are the 4 factors that affect resistance?

There are 4 different factors which affect resistance:The type of material of which the resistor is made.The length of the resistor.The thickness of the resistor.The temperature of the conductor.

How do you reduce resistance in a circuit?

To reduce the circuit to its equivalent resistance, start at the end opposite the source (Emf). Here are the steps: Step 1: Add R2 and R3 in SERIES to get a total of 20 Ohms. Step 2: Add the result of step 1 with R5 in PARALLEL to get 6.7 Ohms.

How do you get the resistance?

Ohms Law and PowerTo find the Voltage, ( V ) [ V = I x R ] V (volts) = I (amps) x R (Ω)To find the Current, ( I ) [ I = V ÷ R ] I (amps) = V (volts) ÷ R (Ω)To find the Resistance, ( R ) [ R = V ÷ I ] R (Ω) = V (volts) ÷ I (amps)To find the Power (P) [ P = V x I ] P (watts) = V (volts) x I (amps)

What happens to resistance when current increases?

This equation, i = v/r, tells us that the current, i, flowing through a circuit is directly proportional to the voltage, v, and inversely proportional to the resistance, r. In other words, if we increase the voltage, then the current will increase. But, if we increase the resistance, then the current will decrease.

What does resistance of a wire depends on?

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. See resistivity.

What is the relationship between resistance and current?

The relationship between current, voltage and resistance is expressed by Ohm’s Law. This states that the current flowing in a circuit is directly proportional to the applied voltage and inversely proportional to the resistance of the circuit, provided the temperature remains constant.