Effect of Temperature on Resistance

Electrical4U
2 Sept 201604:09
EducationalLearning
32 Likes 10 Comments

TLDRThis script delves into the impact of temperature on electrical resistance, particularly in pure metals. It explains that the resistance of metallic conductors increases linearly with temperature, and this variation is directly proportional to the initial resistance as well as the temperature change. The concept of the temperature coefficient of resistance is introduced, illustrating how different materials react uniquely to temperature changes. The discussion also touches on the theoretical notion of superconductivity, where resistance drops to zero, but acknowledges its impracticality in real-world scenarios. The content is presented in a way to enhance understanding and pique interest in the subject matter.

Takeaways
  • 🌑️ The resistance of pure metals increases with an increase in temperature.
  • πŸ“ˆ For metallic conductors, the variation of resistance with temperature is linear.
  • πŸ“Š The change in resistance (βˆ†R) is directly proportional to the initial resistance (R0).
  • πŸ”₯ The change in resistance is also directly proportional to the temperature change (βˆ†T).
  • 🌟 Different metallic conductors show varying changes in resistance for the same temperature change due to their material properties.
  • πŸŽ“ The temperature coefficient of resistance (Ξ±0) quantifies how much a conductor's resistance changes with temperature.
  • πŸ”§ The relationship between resistance and temperature can be expressed with the formula: R = R0(1 + Ξ±0T).
  • ❄️ Below zero degrees centigrade, the resistance of a material continues to decrease as the temperature drops.
  • 🌟 At very low temperatures, certain materials can become superconducting, having zero resistance.
  • 🚫 It is practically impossible for a conductor to have zero resistance, so the resistance vs. temperature graph will not touch the horizontal axis.
  • πŸ“‰ After reaching a certain minimum temperature, the resistance of a conductor will no longer decrease.
Q & A

  • What is the general effect of temperature on the resistance of pure metals?

    -The resistance of pure metals generally increases with an increase in temperature. This is because as temperature rises, the atoms in the metal lattice vibrate more, causing more collisions with the conduction electrons and thus increasing the resistance.

  • How is the variation of resistance with temperature typically represented?

    -The variation of resistance with temperature is often shown as a linear line in a graph, indicating that the change in resistance is directly proportional to the change in temperature.

  • What are R0 and T0 in the context of the script?

    -R0 and T0 represent the initial measured resistance and temperature of the conductor, respectively. These are the baseline values from which changes are measured after the conductor is heated.

  • How does the change in resistance due to temperature change depend on the initial resistance of the conductor?

    -The change in resistance due to temperature change is directly proportional to the initial resistance of the conductor. This means that if the initial resistance is higher, the change in resistance will be more significant, and vice versa.

  • What is the relationship between the change in resistance and the temperature rise?

    -The change in resistance (βˆ†R) is directly proportional to the temperature rise (βˆ†T). This means that a larger temperature increase will result in a larger change in resistance, and vice versa.

  • How does the nature of the material affect the change in resistance with temperature?

    -The nature of the material determines how much the resistance changes with temperature. Different metallic conductors will show different changes in resistance for the same temperature variation due to their unique physical properties.

  • What is the significance of the temperature coefficient of resistance?

    -The temperature coefficient of resistance, denoted as Ξ±0, is a measure of how much the resistivity of a material changes per degree Celsius of temperature change. It is used to calculate the change in resistance due to temperature changes and is specific to the material at 0 degrees Celsius.

  • What is the relationship expressed by the equation RT = R0(1 + Ξ±0T)?

    -The equation RT = R0(1 + Ξ±0T) is used to calculate the resistance (RT) of a material at a given temperature (T) based on its initial resistance (R0) and the temperature coefficient of resistance (Ξ±0). This equation is applicable for both increases and decreases in temperature.

  • What happens to the resistance of a material as the temperature decreases below zero degrees Celsius?

    -As the temperature decreases below zero degrees Celsius, the resistance of the material continues to decrease. If the temperature is lowered further, the material may reach a state of superconductivity, where it has zero resistance. However, this is not practically possible for all materials, and the graph of resistance versus temperature will not touch the horizontal axis but will be parallel to it.

  • What is the concept of superconductivity mentioned in the script?

    -Superconductivity is a state where a material has zero resistance and can conduct electricity without any loss. This occurs at very low temperatures, and while the concept is theoretically possible, it is not practically achievable for all materials.

  • What is the minimum temperature after which the resistance of a conductor will not decrease further?

    -The script does not specify an exact temperature, but it mentions that there is a certain minimum temperature after which the resistance of a conductor will not decrease any further. Beyond this point, the resistance becomes constant regardless of further temperature decreases.

Outlines
00:00
🌑️ Effect of Temperature on Resistance

This paragraph discusses the relationship between temperature and resistance in pure metals, highlighting that resistance increases linearly with temperature. It explains the experimental setup for measuring resistance and temperature, and how heating a conductor affects these values. The change in resistance (Ξ”R) is directly proportional to the initial resistance (R0) and the temperature change (Ξ”T). The concept of the temperature coefficient of resistance (Ξ±0) is introduced, and the formula RT = R0(1 + Ξ±0T) is provided for calculating resistance at different temperatures. The discussion also touches on the concept of superconductivity, where resistance drops to zero at very low temperatures, but acknowledges that this state is not practically achievable for all conductors.

Mindmap
Keywords
πŸ’‘temperature
Temperature is a measure of the degree of hotness or coldness of a body or environment. In the context of the video, it is a critical factor that affects the resistance of materials, particularly metals. As the temperature increases, the resistance of pure metals also increases, which is a linear relationship for metallic conductors.
πŸ’‘resistance
Resistance is the opposition that a material offers to the flow of electric current. In the video, it is discussed that resistance varies with temperature, especially in metallic conductors. The resistance at a given temperature can be calculated and compared to the initial resistance to determine the change due to temperature increase.
πŸ’‘linear relationship
A linear relationship is a direct proportionality between two variables, meaning that a change in one variable results in a proportional change in the other. In the video, the variation of resistance with temperature is described as linear for metallic conductors, indicating that as temperature increases, resistance increases at a constant rate.
πŸ’‘conductors
Conductors are materials that allow the flow of electric current with minimal resistance. In the video, metallic conductors are the focus, and their resistance properties are discussed in relation to temperature changes. The script explains how the resistance of these conductors changes when their temperature is altered.
πŸ’‘initial resistance
Initial resistance refers to the resistance value of a conductor before any change in conditions, such as temperature. In the video, the initial resistance (R0) is a starting point for comparison to understand how much the resistance changes when the temperature is altered.
πŸ’‘temperature coefficient of resistance
The temperature coefficient of resistance is a material-specific constant (denoted as alpha 0) that quantifies the rate of change of resistance with respect to temperature. It is a crucial parameter in understanding how the resistance of a conductor will vary with temperature changes.
πŸ’‘superconducting
Superconductivity is a phenomenon where a material exhibits zero electrical resistance when cooled below a certain critical temperature. In the video, it is mentioned that if the temperature of a material is decreased to a very low value, it can enter a superconducting state, meaning it would conduct electricity without any resistance.
πŸ’‘proportional
Proportional means being in direct proportion, indicating that two quantities are related in such a way that a change in one quantity results in a corresponding change in the other, maintaining a constant ratio. In the video, the change in resistance is said to be directly proportional to both the initial resistance and the temperature change.
πŸ’‘material nature
The nature of a material refers to its inherent properties or characteristics that define its behavior under various conditions. In the context of the video, different metallic conductors have different natures, which means they exhibit different changes in resistance for the same temperature variation.
πŸ’‘minimum temperature
Minimum temperature refers to the lowest temperature a substance can reach under given conditions. In the video, it is mentioned that there is a certain minimum temperature below which the resistance of a conductor no longer decreases, implying that all conductors have a limit to how much their resistance can be reduced.
πŸ’‘graph
A graph is a visual representation of data or relationships between variables. In the video, a graph is used to illustrate the relationship between resistance and temperature, showing how resistance changes as temperature varies.
Highlights

Discussion on the effect of temperature on resistance

Resistance of pure metals increases with an increase in temperature

The variation of resistance with temperature for metallic conductors is linear

Resistance variation is depicted as a linear line in the graph

Measuring resistance and recording temperature at the time of measurement

Heating the conductor to observe changes in resistance and temperature

Initial resistance (R0) and temperature (T0) are the baseline values

The change in resistance is directly proportional to the initial resistance

Change in resistance is also directly proportional to the temperature change

Different metallic conductors show varying changes in resistance for the same temperature change

Expressing the change in resistance as RT - R0 proportional to R0 and Ξ”T

The temperature coefficient of resistance (Ξ±0) is introduced

The resistance equation can be applied for both increases and decreases in temperature

Materials exhibit zero resistance at extremely low temperatures, becoming superconducting

Practical limitations prevent conductors from reaching a state of zero resistance

The graph of resistance versus temperature will not touch the horizontal axis

Resistance becomes constant after reaching a certain minimum temperature

Transcripts

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ThermalEffectElectricalResistanceTemperatureVariationLinearRelationshipSuperconductivityMaterialNatureConductorPropertiesPhysicsPrinciplesTemperatureCoefficientZeroResistanceState