(a) Explain how a gas can be made to conduct electricity. (b) Name the electric charge carriers in gases.
Question 1 Report
(a) Explain how a gas can be made to conduct electricity.
(b) Name the electric charge carriers in gases.
Answer Details
(a) How a gas can be made to conduct electricity
At ordinary pressure a gas is an insulator. It can be made to conduct by ionising it, that is by producing charged particles within it. This is done by applying a very high potential difference across the gas while it is at low pressure (as in a discharge tube), or by heating it strongly, or by exposing it to X-rays, ultraviolet or radioactive radiation. The high field/energy strips electrons from some of the gas atoms, producing free electrons and positive ions; under the applied field these charges drift to the electrodes and so a current flows.
(b) Electric charge carriers in gases
- Positive ions.
- Electrons (together with negative ions).
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