In a discharge tube, most of the gas is pumped out so that electricity is conducted at
Answer Details
A discharge tube is a device that consists of a partially evacuated tube containing a gas at low pressure, and electrodes at each end. When a high voltage is applied across the electrodes, the gas inside the tube becomes ionized and conducts electricity, producing a glowing plasma. In order for this to happen, most of the gas inside the tube needs to be pumped out, leaving only a small amount of gas at low pressure. Therefore, the correct answer is low pressure.