Task: Text Categorization
Input (English): For an RLC circuit, the frequency associated with this effect is where impedance is at a minimum. Substances can be analyzed through a technique that uses the nuclear magnetic form of this effect. That technique's commonly used medical variant is called MRI. This effect causes the amplitude of a system to hit a maximum. For a vibrating string, the frequencies of this are multiples of the fundamental. For 10 points, name this effect where the frequency of the input force equals the natural frequency of the system.
Output (English): Science