JEE Advanced Physics 2014 Paper 1 #10 (#24) RC-Circuit

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At time t=0, terminal A in the circuit shown is connected to B by a key and an alternating current I(t)=I0cos(wt), with I0=1A and w=500rad/s starts flowing in it with an initial direction shown in the figure. At t=7pi/(6w), the key is switched from B to D. (From now on only A and D are connected.) A total charge Q flows from the battery to charge the capacitor fully. If C=20uF, R=10ohm and the battery is ideal with EMF=50V, identify the correct statement(s):
A) Magnitude of the maximum charge on C before t=7pi/(6w) is 1x10^(-3)C.
B) The current in the left part of the circuit just before t=7pi/(6w) is clockwise.
C) Immediately after A is connected to D, the current in R=10A.
D) Q=2x10^(-3)

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[mona]

Why is dq=Idt=coswtdt ? I=Io.coswt no? Thanks.

[sabrine]

Do you have information about what is called that when an electron moves from one orbit to another, it leaves its place in what is called a trou that has the same mass as the electron and the opposite charge?