The atomic radius (r) of an atom can be defined as one half the distance (d) between two nuclei in a diatomic molecule. Atomic radii have been measured for elements. The units for atomic radii are picometers, equal to 10−12 meters
The correct answer is letter A: <span>Unlike junction diodes, point-contact diodes are enclosed in a suitable casing and have terminals for connecting them to a circuit.</span>
