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

Solutions (^) 25 3
whence
q (^) (42 t
a ' b
(t). - v
b

+ 5J-1

a l•

For an instant t from the second time interval, we

find that the fields inside and outside the sphere

are independent, and hence

q 01+ gi (^92) v -q-
sL
vt b 2
Finally, as soon as the sphere absorbs the two
point charges q 1 and q 2 , the current will stop flowing
through the "earthing" conductor, and we can write
/ 3 (t) = 0.
Thus,

• v ( 1 , + 1- ).

1 (t) = —v gr: ,

0,

a

t<^ ,

u~t

a b

<---

3.11.. Taking into account the relation between

the capacitance, voltage, and charge of a capacitor,

we can write the following equations for the three

capacitors:

Cl

q2 q3
(I) ( 1 )0"-- = (PD (PO
1 2
where C1, C2, and C3 are the capacitances of the
corresponding capacitors, and Q1i q 2 , and q 3 are
the charges on their plates. According to the charge
conservation law, q 1 q 2 q 3 = 0, and hence
the potential of the common point 0 is

PAC1+ WBC2+ TDC^3

To= (^) C 1 -1- C2+ C3