Not a popular question among the candidates. The few that attempted it performed poorly. Candidates are expected to know that molecules or atom of the gas has to be ionized under very low voltage. Responses reflected ignorance. Teachers should reach out for coverage of the syllabus.
The expected answers are:
5. (a) The molecules/atoms of a gas must be ionized before the gas can conduct
electricity. Ionisation of the gas requires that the gas pressure is very low within the
enclosure and a very high voltage is applied to the enclosed gas.
(b) Charge carries in gases