Consider the above circuit. The filament lamp A consumes an electrical power PA 100 W when it alone is connected to a voltage of U = 100 V. Filament lamp B consumes a power PB = 20 W when it alone is connected to a voltage of U = 100 V. (a) When the switch is closed, which lamp will be brighter and why? Find the ratio of the levels of brightness of the two lamps assuming their resistances are constant. Assume further that the brightness of a lamp is proportional to the power it consumes. (b) How would your answer change if the lamps were wired in parallel rather than series? U=100 V S