Final answer:
Yes, it is true that radial lead capacitors have two leads extending from the bottom and are marked to identify polarity, typically with a stripe for the negative lead. These capacitors are designed to be mounted on printed circuit boards.
Step-by-step explanation:
It is true that a radial lead capacitor contains two leads that exit the bottom of the capacitor and that a stripe is used to identify the negative lead. Radial lead capacitors are designed to be mounted on printed circuit boards (PCBs), where the leads are inserted into holes in the PCB and then soldered into place.
Cylindrical and spherical capacitors are theoretical models that help us understand how capacitors work. They consist of two concentric conducting materials with charge +Q and -Q. Although these models are important for studying the fundamentals of capacitance, the actual capacitors used in practical applications, like those you see on a PCB, look quite different and include electrolytic, ceramic, and film capacitors—with radial lead capacitors being one common type.