Due to S.C.R in vacuum tube

(A) Absolute electrode potential can be easily measured by using vacuum tube voltmeter. (R ) Oxidation or reduction cannot take place alone,

What is meant by an anode used in vacuum tube?

What is meant by an cathode used in a vacuum tube?

Why vacuum is needed in a vacuum tube?

In metan and vacuume tubes charge carries are

In metals and vacuum tubes charge carriers are

Why to we prefer transistor over the vacuum tubes in the portable radio receivers ?

Write the difference between the electronics devices vacuum tube (valve) and the semiconductor.