Created By : Sunil Kumar Gandipadala

Reviewed By : Phani Ponnapalli

Last Updated : Apr 10, 2023

Free online Wien's Law Calculator tool displays the black body temperature of an object instantly. You just need to provide peak wavelength or peak frequency in the input fields and hit the calculate button to check the output easily.

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Black body temperature:

Steps to Find Black Body Temperature of an Object

The following are the rules and guidelines to solve the black body temperature of an object.

  • Get the peak wavelength of the light from the question.
  • Multiply the peak wavelength by the Wien's displacement constant.
  • Otherwise, check the peak frequency of the light
  • Divide the peak frequency by the constant to get the body temperature.

Wien's Law Formula

Wien's Law or Wien's Displacement Law states that the black body radiation has different temperature peaks at different wavelengths and that is inversely proportional to the temperatures.

The representation of Wien's Law is along the lines

λmax = b/T

Wien's Law representtaion with frequency is given here.

fmax = k * T


λmax is the peak wavelength of light

T is the absolute body temperature of black body

b = 2.8977719 mm*K is the Wien's displacement constant

fmax is the peak frequency

k = 5.878 * 1010 Hz/K is the numerical constant


Question: The wavelength of maximum solar emission is observed to be approximately 0.52 μm. What is the surface temperature of the sun?


Given that,

Maximum wavelength = 4.75 μm = 4.75 x 10-7 m

b = 2.9 x 10-3 m K

Wien's Displacement Law formula is wavelength = b/Temperature

Temperature = b/Waveleength

T = 2.9 x 10-3/4.75 x 10-7

= 6100 K

Therefore, the surface temperature of the sun is 6100K.

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FAQ's on Wien's Law Calculator

1. What are the applications of Wien's displacement law?

Wien's law is used for finding the temperatures of hot radiant objects like stars, sun and it also used for finding the temperature of any radiant object whose temperature is far above that of its surroundings. The applications of Wien's displacement law are the temperature of the sun and incandescent bulb light.

2. What is the value of Wien's constant?

Wien's law constant value is b = 2.8977719 mm*K and the numerical constant used in peak frequency formula is k = 5.8789232 * 1010 Hz/K.

3. What is the formula to calculate the body temperature of an object using Wien's law?

Wien's displacement law have two simple formulas to get the temperature. One is using the peak frequency and the other is using the peak wavelength.

Temperature = b/peak_wavelength

Temperatute = peak_frequency/k

4. The temperature of the human body is 43 deg C. The intensity of radiation emitted by the human body is the maximum at a wavelength?

Given that,

Human body temperature T = 43 + 273 = 316 K

Peak_wavelength = b/Temperature

= 0.002897 mK/316 K

= 9.16 x 10-6

The maximum wavelength is 9.16 x 10-6.