Question
A set of decorative lamps consists of twenty 12 mathrm(~V) lamps in series. If one lamp filament is broken what will the result be? (ET43) A The remainder of the lamps with not be affected B The remainder of the lamps burn more brightly C The remainder of the lamps burn less brightly D All the lamps go out
Answer
4.2
(287 Votes)
Lachlan
Master · Tutor for 5 years
Answer
D
Explanation
If a string of decorative lamps consists of twenty 12V lamps connected in series (one after another so that the current is the same through each one), then each lamp contributes to the total resistance of the circuit. When one lamp fails, that is its filament breaks, it effectively breaks the circuit. In fact, a broken filament means that internally the lamp has an "infinite" resistance which blocks current in the circuit. As a result, no current can flow, and thus, all the lamps turn off. The phiysics rules clearly suggestes that when one lamp breaks in a series circuit connection configuration it affects all the lamps.