630
13 Electromagnetism I
q E + qv d × B = 0
or
E = −V d × B
E = −v d B
(∵ v d ⊥B)
E =
V H
W
= v d B =
j B
ne
=
i B
W t ne
∴
n =
i B
etV H
=
100 × 10
1.6 × 10 −19 × 10 −3 × 5 × 10 −6
= 1.25 × 10
30
/m
3
13.85 If R H is the Hall coefficient, σ the electrical conductivity, then the mobility
μ is given by
μ = R H σ = (−7.3 × 10
−5
) (2 × 10
3
) = −0.146 m
2
/V/s
The magnitude is 0.146 m
2
/V/s .
13 Electromagnetism I
q E + qv d × B = 0
or
E = −V d × B
E = −v d B
(∵ v d ⊥B)
E =
V H
W
= v d B =
j B
ne
=
i B
W t ne
∴
n =
i B
etV H
=
100 × 10
1.6 × 10 −19 × 10 −3 × 5 × 10 −6
= 1.25 × 10
30
/m
3
13.85 If R H is the Hall coefficient, σ the electrical conductivity, then the mobility
μ is given by
μ = R H σ = (−7.3 × 10
−5
) (2 × 10
3
) = −0.146 m
2
/V/s
The magnitude is 0.146 m
2
/V/s .