# What is the relationship between wavelength frequency and temperature

### HubbleSite - Reference Desk - FAQs Thank you for requesting my answer to this question. I won't be giving a mainstream physics answer. My work is different from mainstream theoretical physics. Since temperature affects density, the speed of sound varies with the The relationship between the speed of sound, its frequency, and wavelength is the same. Download/Embed scientific diagram | 3: Relationship between wavelength, frequency and Sea surface temperature as determined from NOAAAVHRR data.

This is therefore the range of infrared wavelengths that pit viper snakes and passive IR cameras must sense. When comparing the apparent color of lighting sources including fluorescent lightsLED lightingcomputer monitorsand photoflashit is customary to cite the color temperature. Although the spectra of such lights are not accurately described by the black body radiation curve, a color temperature is quoted for which black body radiation would most closely match the subjective color of that source.

Note that the informal description of the former bluish color as "cool" and the latter reddish as "warm" is exactly opposite the actual temperature change involved in black body radiation. Discovery[ edit ] The law is named for Wilhelm Wienwho derived it in based on a thermodynamic argument. He showed that, under slow expansion or contraction, the energy of light reflecting off the walls changes in exactly the same way as the frequency. A general principle of thermodynamics is that a thermal equilibrium state, when expanded very slowly, stays in thermal equilibrium.

A modern variant of Wien's derivation can be found in the textbook by Wannier. When Max Planck later formulated the correct black body radiation function it did not explicitly include Wien's constant b. Rather, Planck's constant h was created and introduced into his new formula. From Planck's constant h and the Boltzmann constant k, Wien's constant b can be obtained.

We build devices that are sensitive to the light that our eyes cannot see. Then, so that we can "see" these regions of the electromagnetic spectrum, computer image-processing techniques assign arbitrary color values to the light.

What is a light wave? Light is a disturbance of electric and magnetic fields that travels in the form of a wave. Imagine throwing a pebble into a still pond and watching the circular ripples moving outward. Like those ripples, each light wave has a series of high points known as crests, where the electric field is highest, and a series of low points known as troughs, where the electric field is lowest.

The wavelength is the distance between two wave crests, which is the same as the distance between two troughs. The number of waves that pass through a given point in one second is called the frequency, measured in units of cycles per second called Hertz.

The speed of the wave therefore equals the frequency times the wavelength. What is the relationship between frequency and wavelength? Wavelength and frequency of light are closely related. The higher the frequency, the shorter the wavelength. Because all light waves move through a vacuum at the same speed, the number of wave crests passing by a given point in one second depends on the wavelength.

That number, also known as the frequency, will be larger for a short-wavelength wave than for a long-wavelength wave. The equation that relates wavelength and frequency is: For electromagnetic radiation, the speed is equal to the speed of light, c, and the equation becomes: What is the relationship between wavelength, frequency and energy? The energy of a wave is directly proportional to its frequency, but inversely proportional to its wavelength.

In other words, the greater the energy, the larger the frequency and the shorter smaller the wavelength. Given the relationship between wavelength and frequency described above, it follows that short wavelengths are more energetic than long wavelengths.

How are wavelength and temperature related? All objects emit electromagnetic radiation, and the amount of radiation emitted at each wavelength determines the temperature of the object. Hot objects emit more of their light at short wavelengths, and cold objects emit more of their light at long wavelengths.

The radiation temperature of an object is related to the wavelength at which the object gives out the most light. We call the amount of light emitted at a particular wavelength, the intensity. When you plot the intensity of light from an object at each wavelength, you trace out a smooth curve called a blackbody curve. For any temperature, the blackbody curve shows how much energy intensity is radiated at each wavelength, and the wavelength where the intensity peaks determines the color of that the object. The intensity peak will be at shorter bluer wavelengths for hotter objects, and at longer redder wavelengths for cooler objects. Therefore, you can tell the temperature of a star or galaxy by its color because color is closely related to the wavelength at which its light intensity peaks. Blackbody curves, for objects of all temperatures, have a similar shape, as shown in the graphsbelow.

However, the peak of the curve for a hotter object will be larger more intense than will the peak of the curve for a cooler object. For example, the intensity difference between the peak of the curve for an object at 30, K and the peak of the curve for an object at K body temperature is a factor of 10 billion. This means that a star at 30, K puts out more energy by a factor of 10 billion than does a human at body temperature.

## Wien's displacement law

Because of the large intensity difference, it would be difficult to show both of these curves on the graph below without using logarithms. To plot blackbody curves with large intensity differences on the Heating Up page of Amazing Space's "Star Light, Star Bright", we have made the scale of the intensity axis adjust itself for each temperature change.

How are temperature and color related? The amount of light produced by an object at each wavelength depends on the temperature of the object producing the light. Stars hotter than the sun over 6, degrees C put out most of their light in the blue and ultraviolet regions of the spectrum. Stars cooler than the Sun below 5. Solid objects heated to 1.

Light: Crash Course Astronomy #24

How can light teach us information about the stars? Electromagnetic radiation, or light, is a form of energy.

### Wavelength, Period,Frequency

Visible light is a narrow range of wavelengths of the electromagnetic spectrum. By measuring the wavelength or frequency of light coming from objects in the universe, we can learn something about their nature. Since we are not able to travel to a star or take samples from a galaxy, we must depend on electromagnetic radiation to carry information to us from distant objects in space. 