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 causes increase in resistance?
As electrons move through a metal conductor, some collide with atoms, other electrons or impurities. ... Heating the metal conductor causes atoms to vibrate more, which in turn makes it more difficult for the electrons to flow, increasing resistance.
What is the cause of resistance class 10?
Resistance is caused in a conductor by the free electrons . These free electrons collide with each other and with the ions and atoms that oppose their free movement. This obstruction is known as resistance.
What causes resistors to have resistance?
The number of copper turns controls the resistance very precisely: the more copper turns, and the thinner the copper, the higher the resistance. In smaller-value resistors, designed for lower-power circuits, the copper winding is replaced by a spiral pattern of carbon.
Which is directly proportional to the resistance?
The resistance of any conductor is directly proportional to length and inversely proportional to area of cross-section of the substance. As value of resistance(R) is directly proportional to length of resistance, so by increasing the length of resistance the value of resistance increases.
What is resistance class 10 in simple words?
Resistance is a property of conductor due to which it resists the flow of electric current through it . Component that is used to resist the flow of electric current in a circuit is called resistor. In practical applications, resistors are used to increase or decrease the electric current.
What happen to the current as the resistance increases?
As the resistance increases, the current decreases , provided all other factors are kept constant. Materials with low resistance, metals for example, are called electrical conductors and allow electricity to flow easily.
Is high resistance Good or bad?
The amount of resistance a resistor has is determined by the relationship of the current through it to the voltage across it which determines whether the circuit element is a “good conductor” – low resistance, or a “bad conductor” – high resistance . ... Remember that resistance is always positive, and never negative.
What are examples of high resistance?
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 are the 4 types of resistors?
- Carbon Composition Resistor.
- Thermistor.
- Wire Wound Resistor.
- Metal Film Resistor.
- Carbon Film Resistor.
- Variable Resistor.
- Varistor
- Light Dependent Resistor.
Does higher current increase resistance?
Resistance controls the flow of current. ... Ohms law states that the current flowing in a circuit is proportional to the voltage applied to the circuit, and inversely proportional to the resistance of the circuit. In other words, for a given voltage, the current in the circuit will decrease as the resistance increases .
Do resistors increase resistance?
In a series circuit, adding more resistors increases total resistance and thus lowers current.
Why resistance is 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.
What are the 4 factors that 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.
Is resistance directly proportional to temperature?
The resistance increases as the temperature of a metallic conductor increase, so the resistance is directly proportional to the temperature.
Do you mean by resistance?
Resistance is a measure of the opposition to current flow in an electrical circuit . Resistance is measured in ohms, symbolized by the Greek letter omega (Ω). ... All materials resist current flow to some degree.
