(1 + c)/(r + e + c). The money multiplier (also called the credit multiplier or the deposit multiplier) is a measure of the extent to which the creation of money in the banking system causes the growth in the money supply to exceed growth in the monetary base.
A buzzing light switch could mean the fixture is wearing out, causing an arc of electricity behind the wall plate. If this is the case, the potential for an electrical fire may exist.
Be sure to do this when the light switch is turned off. It is normal for the light in new fluorescent tubes to flicker or appear to swirl in the first 100 hours of operation. If an older tube exhibits these symptoms, turn off the switch, remove the tube, then clean the ends thoroughly. Socket shapes vary, but the tube-removal process is the same.