JAMB - Physics (2019 - No. 32)
The conductivity of gases at low pressure can be termed as
I. hot cathode emission
II. thermo ionic emission
III. cold cathode emission
IV. Field emission
I. hot cathode emission
II. thermo ionic emission
III. cold cathode emission
IV. Field emission
I & II
II & III
III & IV
IV & V
解释
As conduction of gases is at low pressure and high voltage, called field or cold cathode emission.