To calculate the wavelength of the radiation, knowing the frequency and speed of propagation of this radiation, divide the second value by the first. If instead frequency a certain period, multiply it by the speed of propagation of the radiation. Finally, if a known cyclic frequency of radiation, multiply the speed by 2π and then divide the result on the cyclic frequency.
So the result in the SI system, pre-put in it all the values from the problem statement. Then turn the result back into the units used.
If the radiation is light, the length of its waves in vacuum, determine the eye: red - from 635 to 690 nm, orange 590 yellow, from 570 to 580, green - from 510 to 520, the blue from 440 to 480, the purple from 380 to 400.
Having a special device - a spectrometer to determine the wavelength of light can be more accurate than the eye. If it is polychromatic, to determine its spectral composition is possible only with the help of this device For this channel luminous flux in the input window of the device. It passes through the gap perpendicular to the prism, and then through the prism, and then will enter either on the gauge or on the sensor. In the second case, processing of the measurement result will realize the electronic unit.
To find the wavelength of the radiation of the decimeter or centimeter range, connect the antenna to the wavemeter, and then begin gradually to change its size. When it becomes equal to the half wavelength, the reading of the wavemeter will be maximum.
Direct a thin beam of light perpendicularly to the diffraction grating. The screen will display a number of spots. Measure the angle between an imaginary line continuing the course of the beam after the grating, the line connecting the entry point of the beam in a grid with the first of the spots. Find the sine of that angle and then multiply by the distance between two adjacent lines of the lattice. Get the wavelength, which is expressed in the same units as the distance between the lines.