To calculate the wavelength of an electromagnetic wave, you can use the equation:
wavelength = speed of light / frequency
The speed of light is approximately 3.0 x 10^8 meters per second.
Given that the frequency is 1.2 x 10^11 Hz, we can substitute these values into the equation:
wavelength = (3.0 x 10^8 m/s) / (1.2 x 10^11 Hz)
wavelength ≈ 2.5 x 10^-3 meters or 2.5 millimeters
Therefore, the wavelength of infrared light with a frequency of 1.2 x 10^11 Hz is approximately 2.5 millimeters.