Calculate the equivalent resistance of the following combination of resistors undefined between $\mathrm{A} \mathrm{and} \mathrm{B}$.

What will an alpha particle change into when it absorbs one electron?

What will an alpha particle change into when it absorbs two electrons?

Of the three connecting wires in a household circuit: Which two of the three wires are at some potential?

Of the three connecting wires in a household circuit: In which of the three wires should the switch be connected?