66.
(a) Since K = qV we have K
p
= K
d
=
1
2
K
α
(as q
α
= 2K
d
= 2K
p
).
(b) and (c) Since r =
√
2mK/qB
∝
√
mK/q, we have
r
d
=
m
d
K
d
m
p
K
p
q
p
r
p
q
d
=
(2.00 u)K
p
(1.00 u)K
p
r
p
= 10
√
2 cm = 14 cm ,
r
α
=
m
α
K
α
m
p
K
p
q
p
r
p
q
α
=
(4.00 u)K
α
(1.00 u)(K
α
/2)
er
p
2e
= 10
√
2 cm = 14 cm .