The phenomenon of absorption of certain frequencies of radio and microwave radiation by atoms placed in a magnetic field. The pattern of absorption reveals molecular structure. Absorption or emission of electromagnetic radiation by electrons or atomic nuclei in response to certain magnetic fields. The principles of magnetic resonance are used to study the atomic and nuclear properties of matter; two common laboratory techniques are nuclear magnetic resonance and electron spin resonance. In medicine, magnetic resonance imaging is used to produce images of human tissue
resonance of electrons or atoms or molecules or nuclei to radiation frequencies as a result of space quantization in a magnetic field