(a) electrons only
(b) positive and negative ions
(c) electrons and positive ions
(d) electrons, positive ions and negative ions
Correct Answer: (d) electrons,
positive ions and negative ions
Explanation
In gases, ionization
produces free electrons and both types of ions, all of which
contribute to current flow.
Notes for
More Information
•
Gas conduction requires
ionization
•
Used in neon lamps and arc
discharges
•
Ohm’s law is not strictly obeyed
•
In liquids and gases,
electric current is not carried only by electrons, unlike in solids.
•
In these mediums, current is
carried by electrons, positive ions, and negative ions.
•
Normally, gases act as
insulators and do not allow current to flow.
•
When a high voltage or
strong electric field is applied, the gas becomes ionized.
•
Ionization means electrons are
removed from gas atoms or molecules.
•
Ionization creates free
electrons (negative charges).
•
It also creates positive
ions (atoms that have lost electrons).
•
Sometimes, free electrons attach
to neutral atoms and form negative ions.
•
Electrons move
towards the positive terminal (anode).
•
Positive ions move
towards the negative terminal (cathode).
•
Negative ions, if
formed, move in the same direction as electrons.
•
All these moving charges
contribute to the flow of electric current.
•
The total current in
a gas is the combined effect of:
o
Electrons
o
Positive ions
o
Negative ions
•
Therefore, the most correct and
complete answer is electrons, positive ions, and negative ions.
•
This type of current flow is
observed in devices like fluorescent tubes, neon lamps,
and natural phenomena like lightning.
