Which statement is true about resistance?
The answer is C. The resistance increases as the current decreases. Explanation: The resistivity of conductors, semiconductors, and insulators depend on temperature.
How do you describe 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). Conductors: Materials that offer very little resistance where electrons can move easily. Examples: silver, copper, gold and aluminum.
What is resistance and how does it work?
Resistance measures a materials ability to resist the flow of electrons through it. If the width of the hose at the bottom remains the same, then by adding more water to the tank, the water through the hose flows faster. Similarly, adding more voltage to a circuit increases the current.
What does a resistance do?
A resistor is a passive two-terminal electrical component that implements electrical resistance as a circuit element. In electronic circuits, resistors are used to reduce current flow, adjust signal levels, to divide voltages, bias active elements, and terminate transmission lines, among other uses.
When resistance increases what happens to voltage?
This means that increasing the voltage will cause the current to increase, while increasing the resistance will cause the current to decrease. Knowing any two of the three parameters allows us to calculate the third, unknown parameter.
Is voltage directly proportional to resistance?
In other words, the current is directly proportional to the voltage and inversely proportional to the resistance. So, an increase in the voltage will increase the current as long as the resistance is held constant. If the current is held constant, an increase in voltage will result in an increase in resistance.
What happens if resistance increases?
The relationship between resistance and wire length is proportional . When resistance is increased in a circuit , for example by adding more electrical components , the current decreases as a result.
What are the factors affecting 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.
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.
Does temperature affect resistance?
Heating a metal conductor makes it more difficult for electricity to flow through it. These collisions cause resistance and generate heat. Heating the metal conductor causes atoms to vibrate more, which in turn makes it more difficult for the electrons to flow, increasing resistance.
Is heat directly proportional to resistance?
This is exactly as you have stated, the heat is directly proportional to the resistance and the square of the current. Because the current term is squared in the power equation, the heat given off by the circuit is more highly dependent on the current flowing through it than the resistance.
Does higher resistance produce more heat?
A higher resistance produces more heat. The longer the time the larger the amount of heat produced. The amount of current, I. the higher the current the larger the amount of heat generated.
What is the relation between resistance and heat produced?
Heat= Power×time. Therefore H is inversely proportional to R. Therefore H is directly proportional to R.
What is relation between current and heat?
Joule’s law states the amount of heat production in a conductor is : Directly proportional to the square of electric current flowing through it. Is directly proportional to the resistance of the conductor. Directly proportional to the time for which electric current flows through the conductor.
Why the heat decreases even after increasing the resistance?
If H=V2Rt ,then increasing resistance means decreasing the heat produced. Implies that the voltage V stays constant. So with V=IR if V stays constant and the resistance R increases then the current I decreases.