Fig. 21.
Fig. 22.
1
3.84. (a) E1 = 2sE0/(e + 1), E 2 = 2E0/(e + 1), D1 = D2 =
2860E0/(e + 1); (b) E1 = Eo, E2 = EVE, D 1 = D2 = a0E0.
3.85. (a)
= E2 = Eo, D1= 80E0, D2 = 8D1; (b)
E2
= 2E0/(e + 1), D1 = 2e0E0/(e + 1), D2 = 8131.
3.86. E = q/2ne, (e + 1) r2.
3.87. p = poe/(e — 1) = 1.6 g/cm3, where a and po are the permittivity and density of kerosene.
3.88. cr;flax = (e — 1) NE = 3.5 nC/m2,
nR2 (e — 1) 80E=
= 10 pC.
3.89. (a) Since the normal component of the vector D is continuous at the dielectric interface, we obtain
= —ql (e — 1)/2nr3 (e + 1), for 1
0 and a' -4- 0;
(b) q' = —q (8 — 1)/(e + 1).
3.90. F = q2 (a — 1)/161te012 (e + 1).
q/2n (1 + e) r2 in vacuum,
3.91. D = eq/2n (1 + e) r2 in dielectric;
E = q/2neo (1 + e) r2
cp = q/2neo (1 + e) r
both in vacuum and in dielectric.
3.92. a' = ql (8 — 1)/2nr3e (e -I- 1); for 1
0 and a'
0.
3.93. a' = ql (a — 1)/2nr3e.
3.94. E1 = Ph/eod (between the plates), E2. = —(1 — h/d)P/c o,
= D2 = Phld.
3.95. p' = —2a, i.e. is independent of r.
3.96. (a) E =
3.97. E0 = E — P/360.
3.98. E = 3E0/(e + 2), P = 3e0E0 (e — 1)/(a + 2).
3.99. E
—P/280.
3.100. E = 2E0/(e + 1); P = 280E0 (e
1)/(e + 1).
3.101. C —
4neoaR1
1-1-(8-1) R1/R2 '
3.102. The strength decreased
1/2 (e + 1)
times; q =
=112C6 (8 — 1)/(e
1).
S
81- 82
3.103. (a) C = d1/e1
80
±d2/e2 ; (b) a' = eoT7 8,42+ 82di .
3.104. (a) C= co (e2 — el) Sid In (e2/e1); (b) p' = — q(e2 — ei)/dSe2.