Why do some substances absorb EMR more than others?

Thread starter LogicalAcid
Start date Nov 21, 2010

In summary, substances absorb electromagnetic radiation (EMR) based on their molecular structure and the energy levels of their electrons. The type of EMR affects the absorption rate, with different substances having varying abilities to absorb specific types. Factors like density and chemical composition also contribute to absorption. The absorption of EMR can be controlled by manipulating molecular structure and composition, which has practical applications such as creating materials with specific optical properties. The absorption of EMR by substances impacts daily life in various ways, from determining the color of objects to playing a crucial role in technologies like solar panels.

Nov 21, 2010

LogicalAcid

Some are closer to black bodies than others, some reflect more than others, why is this?

Physics news on Phys.org

Nov 22, 2010

MagnetDave

There's a ton of reasons why, but it comes down mainly to:

Material (specifically EM properties, more specifically EM properties relative to the medium its in)
Surface Finish
Geometry

1. Why do some substances absorb more electromagnetic radiation (EMR) than others?

Substances absorb EMR based on their molecular structure and the energy levels of their electrons. Some substances have a molecular structure that allows them to absorb a wider range of EMR wavelengths, while others have electrons with energy levels that are easily excited by EMR, making them more efficient at absorbing it.

2. How does the type of EMR affect the absorption by different substances?

The type of EMR, such as visible light, infrared, or ultraviolet, determines the wavelength and energy of the radiation. Different substances have different molecular structures and energy levels, which make them more or less likely to absorb specific types of EMR.

3. What factors besides molecular structure contribute to the absorption of EMR by substances?

Besides molecular structure, the density and chemical composition of a substance also play a role in its ability to absorb EMR. For example, denser substances may have more molecules that can interact with the EMR, while substances with specific chemical properties, such as metals, may have a higher absorption rate.

4. Can the absorption of EMR by substances be controlled?

Yes, the absorption of EMR by substances can be controlled by manipulating their molecular structure and composition. For example, by changing the chemical composition of a substance, scientists can alter its ability to absorb specific types of EMR. This is useful in various applications, such as creating materials with specific optical properties.

5. How does the absorption of EMR by substances impact daily life?

The absorption of EMR by substances has a significant impact on our daily lives. For example, it determines the color of objects we see, as different substances absorb and reflect different wavelengths of visible light. It also plays a crucial role in technologies like solar panels, which rely on substances that can efficiently absorb and convert sunlight into energy.