(a) electrons
(b) protons
(c) electrons and ions
(d) charged particles
Correct Answer: (a)
electrons
Explanation
In metallic conductors, electric
current is caused by the drift of free electrons under the
action of an electric field. Protons are tightly bound in the nucleus and
cannot move.
Notes for
More Information
· Metals
contain a large number of free electrons
· Direction
of electron flow is opposite to conventional current
· Current is
measured in ampere (A)
· Electric
current flows because of the movement of mobile charge carriers.
· In
semiconductors, the mobile charge carriers are electrons and holes.
· Free
electrons can move freely inside the material.
· Holes (absence
of electrons) also behave like positive charge carriers and can move.
· The
movement of electrons and holes together produces electric current in
a semiconductor.
· Ions do not
move inside a semiconductor.
· Since ions
are immobile, they do not contribute to electric current.
