U1 = Q / C1
U2 = Q / C2
U3 = Q / C3

Tong hieu dien the:

U = U1 + U2 + U3
= Q(1/C1 + 1/C2 + 1/C3)

Tinh dien dung tuong duong:

1/Ctd = 1/C1 + 1/C2 + 1/C3
= 1/(2×10^-9) + 1/(4×10^-9) + 1/(6×10^-9)

= (1/2 + 1/4 + 1/6) ×10^9
= (6/12 + 3/12 + 2/12) ×10^9
= 11/12 ×10^9

=> Ctd = 12/11 ×10^-9 F

Tinh dien tich khi U = 1100 V:

Q = Ctd × U
= (12/11 ×10^-9) × 1100
= 1,2×10^-6 C

Tinh hieu dien the tren moi tu:

U1 = Q/C1 = (1,2×10^-6)/(2×10^-9) = 600 V
U2 = Q/C2 = 300 V
U3 = Q/C3 = 200 V

So sanh:

U1 = 600 V > 500 V (vuot gioi han)

VM = kQ / rM
VN = kQ / rN

Hieu dien the:

UMN = VM - VN = kQ(1/rM - 1/rN)

Thay rM = 1 m, rN = 2 m:

UMN = kQ(1 - 1/2) = kQ/2

b) Tinh cong:

A = qUMN

UMN = (9×10^9 × 8×10^-10) / 2 = 3,6 V

q = -1,6×10^-19 C

A = qUMN = (-1,6×10^-19) × 3,6
= -5,76×10^-19 J

Ket qua:

UMN = 3,6 V
A = -5,76×10^-19

VM = kQ / rM
VN = kQ / rN

Hieu dien the:

UMN = VM - VN = kQ(1/rM - 1/rN)

Thay rM = 1 m, rN = 2 m:

UMN = kQ(1 - 1/2) = kQ/2

b) Tinh cong:

A = qUMN

UMN = (9×10^9 × 8×10^-10) / 2 = 3,6 V

q = -1,6×10^-19 C

A = qUMN = (-1,6×10^-19) × 3,6
= -5,76×10^-19 J

Ket qua:

UMN = 3,6 V
A = -5,76×10^-19