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Physics
Physics
Problem
Which one of the following expressions gives the current density
J
J
J
in a conductor in terms of the number density of charge carriers
n
n
n
, elementary charge
e
e
e
and drift velocity
v
d
v_d
v
d
? a)
1
2
n
e
v
d
\dfrac{1}{2}\,n e v_d
2
1
n
e
v
d
b)
n
e
v
d
n e v_d
n
e
v
d
c)
2
n
e
v
d
2 n e v_d
2
n
e
v
d
d)
n
e
v
d
2
\dfrac{n e v_d}{\sqrt{2}}
2
n
e
v
d
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