Consider the circuit shown in the diagram below. Switch 1 has been closed for a
ID: 1379803 • Letter: C
Question
Consider the circuit shown in the diagram below. Switch 1 has been closed for a long time. The capacitor is initially uncharged.
a) Now switch S2 is closed. What happens to the brightness of (current through) each of the bulbs immediately after switch S2 is closed? Explain your reasoning.
b) Compare the brightness of the bulbs after switch S2 has been closed for a long time. Explain your reasoning.
c) If, after the switch S2 has been closed for a long time, switch S1 is then opened, how would the brightness of the bulbs compare over time? (Switch S2 remains closed.) Explain your reasoning.
Explanation / Answer
a)
switch 1 is closed so current flows through circuit consisting of two bulbs
when switch 2 is closed under steady state conditions capacitor will be open circuited
capacitor starts to charging with negative polarity
BULB A GLOWS BRIGHTER
BULB B BRIGHTNESS DECREASES DUE TO CAPACITOR EFFECT
c)
when switch 1 is opened BULB A acts as open circuit
there is no current flowing through BULB A
IT WILL NOT GLOW
but BULB B glows brighter because capacitor starts discharging