Aptitude Test Problems in Physics Science for Everyone by S Krotov ( PDFDrive.com )

(^270) Aptitude Test Problems in Physics
When the key is switched to position .1, the
charge on the capacitor will change during a short
time interval At by
At (vi— fist)
Rl
When the key is switched to position 2, the charge
will change by
At (fs—Ust)
R2 •
During cycle, the total change in charge must be
zero:
(C—Ust) (Ws—List)
—0.
RI (^) R 2
Hence the voltage Ust and the capacitor charge qst
in the steady state can be found from the formulas
Iti 2 /1 1 + 1ftRs
lust— RI-I-Rs
CUst— C (g2R1+ CR2)
R1+ R' •
3.37. A direct current cannot pass through the
capacitors of capacitance C^1 and C2. Therefore,
in the steady state, the current through the current
source is
(^1) =
r-FR 2 •
Since the capacitors are connected in series, their
charges q will be equal, and
Cl
Consequently,
*R 2 C 1 C 2
q
(r+ R 2 ) (Ci+ C2)