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Whenever a radiometer is advertised in a catalog, it is said to be contained in a partial vacuum. This deceives the shopper into thinking the radiometer is in a vacuum, and there is no air.

Because of this, the movement of a radiometer is often wrongly attributed to the momentum of light particles (photons), but not the movement of air. The shiny (or white) surface reflects most incoming photons, and gains twice the photon momentum of the black surface, which absorbs most photons, and gains their momentum only once. In a vacuum, this would result in a rotor movement in the direction of the black surface. In other words, the radiometer rotates so that the leading surface is the black side.

A look at your radiometer reveals that the opposite is true. In fact, this movement is caused by the black surface absorbing photon energy and heating the air near it. Hot air molecules move faster than cold ones and, by bumping onto the surface, some transmit their momentum to the black sides of the rotor. The force of the photon momentum is very small compared to that of the hot air molecules, thus the rotor moves towards the cooler, shiny (or white) surface.


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What kind of energy powers a radiometer?

A radiometer is powered by light energy. When light is absorbed by the vanes of the radiometer, it creates a temperature difference that causes the vanes to rotate. This rotation is a demonstration of the conversion of light energy into mechanical energy.


What energy transformation are taking place with the radiometer?

In a radiometer, light energy is converted into rotational kinetic energy. The light causes the vanes inside the radiometer to spin due to the pressure exerted by the photons on the reflective surfaces of the vanes.


Why is it important for light energy to be absorbed in a radiometer?

In a radiometer, light energy is absorbed by the vanes, causing them to heat up. This creates a temperature difference between the inside and outside of the vanes, leading to a pressure difference that causes them to spin. Absorption of light energy is crucial for the radiometer to convert light into mechanical energy and demonstrate its functionality.


What is the energy transformation for radiometer?

In a radiometer, light energy is converted into kinetic energy. When light is absorbed by the dark side of the vanes, it causes the molecules inside to heat up and move faster, resulting in the rotation of the vanes.


What happens after the light is absorbed by a radiometer?

After the light is absorbed by a radiometer, the black and white vanes inside start to rotate due to the thermal expansion of the air molecules around them. The rotation occurs because the black side absorbs more light and heats the air more than the white side, causing a pressure difference that drives the movement.

Related Questions

What is a sentence with the word radiometer?

The lamp is then scanned using a filter radiometer under computer control.


What kind of energy powers a radiometer?

A radiometer is powered by light energy. When light is absorbed by the vanes of the radiometer, it creates a temperature difference that causes the vanes to rotate. This rotation is a demonstration of the conversion of light energy into mechanical energy.


What energy transformation are taking place with the radiometer?

In a radiometer, light energy is converted into rotational kinetic energy. The light causes the vanes inside the radiometer to spin due to the pressure exerted by the photons on the reflective surfaces of the vanes.


The sun's energy is measured using what?

a radiometer


What is used to measure energy from the sun?

Radiometer


What predicts how a pattern may continue?

A radiometer.


What converts light into mechanical energy?

A radiometer


What measures the energy from the sun?

well the energy ........


Where can people buy the cheapest radiometer?

Someone can buy the cheapest radiometer usually from mass online retailers such as Amazon and eBay that often have and sell radiometers at a cheap price.


Why is it important for light energy to be absorbed in a radiometer?

In a radiometer, light energy is absorbed by the vanes, causing them to heat up. This creates a temperature difference between the inside and outside of the vanes, leading to a pressure difference that causes them to spin. Absorption of light energy is crucial for the radiometer to convert light into mechanical energy and demonstrate its functionality.


What instrument is used to locate a uranium?

A gamma radiometer or a gamma spectrometer.


What is the energy transformation for radiometer?

In a radiometer, light energy is converted into kinetic energy. When light is absorbed by the dark side of the vanes, it causes the molecules inside to heat up and move faster, resulting in the rotation of the vanes.