# What are the amplitudes called for blue visible light, and microwaves?

• FisherDude
In summary, the amplitude of sound waves is referred to as volume, while for blue visible light and microwaves, it is referred to as intensity. This terminology is the same, but the measurements and units used differ due to the different frequencies and scales involved. While sound and radio waves can be measured with classical concepts, light is better understood through photon and quantum efficiencies. This is evident in the difference between the output of a sound transducer and a photodiode.

#### FisherDude

The amplitude of sound waves is commonly referred to as volume. What about for blue visible light, and microwaves? I'm guessing for the first one it's brightness. Btw I'm looking for a word answer, not the magnitude of the amplitude (not a numerical amplitude)

Intensity. Amplitude. The question sounds more like a dictionary rather than a physics question.

Btw, blue light and microwaves are different frequencies, not amplitudes. But mathman is right - the terminology is the same.

Minority viewpoint: there is an interesting question behind this. Professional sound folks measure SPL ... sound pressure level ... to assess the amplitude or volume of sound. RF people measure 'Volts Per Meter' from a Field Strength meter as a measure of the E field of a source, and call it field strenth or intensity. By the time you get to light we don't measure the peak of the electric field, we measure the intensity, the average energy delivered, and we do that with detectors that have a 'quantum efficiency'.

So on the one hand, they are all the same thing: amplitude is amplitude. On the other hand, the huge change (sound at kilohertz to light at 100's of terrahertz) in scale allows us to use comfortable classical concepts for sound and radio waves, while light is better handed with photon and quantum efficiencies.

If you think this doesn't matter, consider the difference in output from a sound transducer, which outputs a waveform proportional to the pressure field, and the output from a photodiode, which outputs a current proportional to the incident light energy (# electrons proportioanl to # photons).

## 1. What is the amplitude of blue visible light?

The amplitude of blue visible light is typically around 450-495 nanometers. This is the measurement of the distance between the peaks of the light waves.

## 2. How does the amplitude of blue visible light compare to other colors?

Blue visible light has a shorter wavelength and higher frequency than red visible light, which has a longer wavelength and lower frequency. This means that blue light has a higher amplitude than red light.

## 3. What is the amplitude of microwaves?

The amplitude of microwaves can vary depending on the specific frequency and wavelength, but it is typically in the range of 1 millimeter to 1 meter. This is much larger than the amplitude of visible light.

## 4. How do the amplitudes of microwaves and visible light affect their properties?

The amplitude of a wave affects its energy and intensity. Higher amplitude waves have more energy and can be more intense. This is why microwaves, with their larger amplitudes, can penetrate and heat up food more effectively than visible light.

## 5. Can the amplitude of a wave be changed?

Yes, the amplitude of a wave can be changed by altering the energy or force that is causing the wave. For example, a light bulb can be dimmed to decrease the amplitude of the light waves it emits, or a microwave oven can be adjusted to change the amplitude of the microwaves it produces.