Which metal expands more in a bimetallic strip?
2 Answers
In a bimetallic strip, the metal that expands more is typically the one with the higher coefficient of thermal expansion. Commonly used pairs are brass and steel, where brass expands more than steel. This difference in expansion rates causes the strip to bend when heated, which is useful in applications like thermostats and temperature sensors.
In a bimetallic strip, two different metals are bonded together. When the strip is subjected to temperature changes, the different rates at which the metals expand or contract cause the strip to bend. The metal that expands more with temperature increase will be on the outer side of the curve, while the metal that expands less will be on the inner side.
To determine which metal expands more, you need to look at their coefficients of thermal expansion. The coefficient of thermal expansion (\(\alpha\)) is a measure of how much a material expands per degree change in temperature. A higher coefficient means that the metal will expand more for a given temperature increase.
Here’s a step-by-step guide to understanding which metal expands more in a bimetallic strip:
1. **Identify the Metals**: Determine which two metals are used in the bimetallic strip. Common pairs include iron and brass, or steel and aluminum.
2. **Find the Coefficients of Thermal Expansion**: Look up the coefficients of thermal expansion for each metal. For example, brass has a coefficient of about 19 × 10^-6 /°C, while steel has a coefficient of about 12 × 10^-6 /°C.
3. **Compare the Coefficients**: The metal with the higher coefficient of thermal expansion expands more when heated. For instance, in the case of brass and steel, brass expands more than steel.
4. **Observe the Behavior**: When the bimetallic strip is heated, the metal with the higher coefficient of thermal expansion will expand more, causing the strip to bend with this metal on the outside of the curve.
So, if you have a bimetallic strip made of two different metals, the metal with the higher coefficient of thermal expansion is the one that expands more.
To determine which metal expands more, you need to look at their coefficients of thermal expansion. The coefficient of thermal expansion (\(\alpha\)) is a measure of how much a material expands per degree change in temperature. A higher coefficient means that the metal will expand more for a given temperature increase.
Here’s a step-by-step guide to understanding which metal expands more in a bimetallic strip:
1. **Identify the Metals**: Determine which two metals are used in the bimetallic strip. Common pairs include iron and brass, or steel and aluminum.
2. **Find the Coefficients of Thermal Expansion**: Look up the coefficients of thermal expansion for each metal. For example, brass has a coefficient of about 19 × 10^-6 /°C, while steel has a coefficient of about 12 × 10^-6 /°C.
3. **Compare the Coefficients**: The metal with the higher coefficient of thermal expansion expands more when heated. For instance, in the case of brass and steel, brass expands more than steel.
4. **Observe the Behavior**: When the bimetallic strip is heated, the metal with the higher coefficient of thermal expansion will expand more, causing the strip to bend with this metal on the outside of the curve.
So, if you have a bimetallic strip made of two different metals, the metal with the higher coefficient of thermal expansion is the one that expands more.