Three identical bulbs are connected as shown in the figure below. Each bulb has a resistance R.
(a) Which bulb(s) is/are brighter and which is/are dimmer? Explain your answers.
(b) If lamp Z is disconnected, state whether bulb X and Y becomes brighter or dimmer, or their brightness stays the same.
Explain your answers.
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Answer:
(a) Bulb X will be brighter than bulbs Y and Z. This is because current through X is greater than current through Y or Z.
(b) Bulb X will be dimmer and bulb Y will be brighter. This is because total resistance has increased, and hence less current flows through X, resulting in bulb X being dimmer.
However, because Z is disconnected, more current flows through Y now. This results in bulb Y being brighter.
