Just after the switch is closed: what is the potenial difference across bulb A,
ID: 2174914 • Letter: J
Question
Just after the switch is closed: what is the potenial difference across bulb A, across bulb B, across the capacitor, and across the battery? explain please. Rank the currents through bulb A, bulb B, the capacitor, and the battery. explain
A long time after the switch is closed: rank the currents through bulb a, bulb b, the capacitor, and the battery. explain. What is the potential difference across bulb a, across bulb b, across the capacitor, and across the battery? explain
summerize the results by describing the behavoir of bulb a and of bulb b from just after the switch is closed until a long time later.
Explanation / Answer
suppose that both the bulbs are identical and have a resistance of R and volatge supplied by battery be V
just after the switch is closed,the potential difference across the capacitor is zero because the charge cannot change instantaneously.
so the potential difference across bulb B is also zero.
so the total drop is across bulb A i.e V and current through bulb A = current through capacitor.
and current through bulb B = 0.
so iA = iC > iB .
the potential difference across battery does not change. it remains to be V.
after a long time when steady state is reached, the charge in the capacitor becomes constant. so there is no current flow through the capacitor.
the current through bulb A = current through bulb B
and as resistances are assumed to be the same, the potential difference across bulb A = potential difference across bulb B = V/2
the potential difference across battery does not change. it remains to be V.
the rank of currents = iA = iB >iC
from the above discussion we can say that initially only bulb A will be glowing just after the switch is closed and finally after a long time both will glow with same brightness.
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