Of Modern Physics - Applications

Tunneling was initially used to explain radioactive decay (alpha particles escaping the nucleus). Now, it is engineered.

A photon strikes a silicon semiconductor. If its energy exceeds the bandgap, it knocks an electron loose, creating an electron-hole pair. A built-in electric field (p-n junction) separates the charges, driving them through an external circuit as usable electricity. Applications Of Modern Physics

This is applied Quantum Mechanics . Hydrogen nuclei (single protons) spin like tiny magnets. In an MRI machine, a powerful magnetic field aligns these spins. A radio wave pulse knocks them out of alignment. As they "relax" back, they emit signals. Because water density varies in tumors vs. healthy tissue, MRI creates exquisite 3D images. Tunneling was initially used to explain radioactive decay