Resistance of an element

In summary: Then you just add up all of these small voltages to get the total voltage drop across the entire resistor. This is known as Kirchhoff's Voltage Law.In summary, the resistance of a uniform resistor element increases from 0 at the beginning to R at the end of the resistive element that is L. This is also true for wire wound resistors, but the resistance increases in steps. A voltage drop across a resistor is the sum of the small voltage drops within the resistor, which is known as Kirchhoff's Voltage Law.
  • #1
Physicslearner500039
124
6
Hi All,

I have this clarification, if I have a resistor element of any value and if the physical length of the resistor is say L. Does the resistance of the element increases from 0 at the beginning to R at the end of the resistive element that is L, or it is the average, or it is located at one point, could somebody please explain me this? Similarly if a current I is flowing through the resistive element the voltage drop say Vr keeps increasing from 0 to the Vr at the end of the element or how it is?

Thanks in advance,
regards,
Satya
 
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  • #2
It depends on the resistor, but if the resistance material is uniform, then this is true:

if I have a resistor element of any value and if the physical length of the resistor is say L. Does the resistance of the element increases from 0 at the beginning to R at the end of the resistive element that is L,

Wire wound resistors are similar, but the resistance increases in steps as you go from turn to turn. If you followed the wire all the way around the resistor, then the resistance increases as you go from one end to the other.

There are potentiometers of both types which allow you to connect to various ponts on a resistor and gradually change the resistance or the ratio of resistances..
 
  • #3
So can I say that a voltage drop across a resistor (by passing a current) is the sum of the small voltage drops within the resistor ?

Thanks in advance,
Regards,
Satya
 
  • #4
Yes, you could say that.

The small parts of a resistor are just like having a lot of small resistors in series, so you could regard each of them as producing a small voltage due to the current flowing in it.
 
  • #5


Hello Satya,

The resistance of an element is a measure of its ability to resist the flow of current. It is typically represented by the letter R and is measured in ohms (Ω). The resistance of an element is determined by its physical characteristics, such as length, cross-sectional area, and material composition.

In the case of a resistor element, the resistance does not increase from 0 at the beginning to R at the end. Rather, the resistance is constant throughout the entire length of the element. This means that the voltage drop across the element is also constant, regardless of where it is measured along the element's length. Therefore, the voltage drop Vr at the end of the element is the same as the voltage drop at any other point along the element.

To understand this concept, it may be helpful to think of a resistor element as a pipe through which water (current) flows. The resistance is like the diameter of the pipe - a wider pipe will allow more water to flow through at a given pressure (voltage). However, the resistance remains the same throughout the entire length of the pipe.

I hope this helps clarify your question. Please let me know if you have any further questions.

Best,
 

What is resistance?

Resistance is a measure of how much a material or component impedes the flow of electrical current. It is measured in units of ohms (Ω).

What factors affect the resistance of an element?

The resistance of an element is affected by several factors, including the material it is made of, its length, its cross-sectional area, and its temperature.

How is resistance calculated?

Resistance can be calculated using Ohm's Law, which states that resistance (R) is equal to voltage (V) divided by current (I), or R = V/I. It can also be calculated using the formula R = ρL/A, where ρ is the resistivity of the material, L is the length of the element, and A is the cross-sectional area.

What is the relationship between resistance and conductance?

Resistance and conductance are inversely proportional to each other. As resistance increases, conductance decreases, and vice versa. Conductance is the measure of how easily electricity can flow through a material.

How does temperature affect resistance?

In most materials, an increase in temperature leads to an increase in resistance. This is because as the temperature rises, the atoms in the material vibrate more, which hinders the flow of electrons and increases resistance. However, in some materials such as semiconductors, an increase in temperature can actually decrease resistance.

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