Question

Cathode rays are produced when the pressure is of the order of
(a) 2 cm of Hg
(b) 0.1 cm of Hg
(c) 0.01 mm of Hg
(d) 1 μm of Hg

Answer 1

option c is correct....

Answer 2

Answer:

c) 0.01 mm of Hg

Explanation:

Cathode rays are the streams of fast moving electron, that always travel in straight lines. The rays are generally emitted from the cathode surface and their direction is independent of the position of the anode.

These can be produced by using a discharge tube that contains the gas at a low pressure of the order of 10-²mm of Hg.  The cathode rays in the discharge tube are the electrons that are produced due to ionisation of gases that are emitted by cathode due to the collision of positive ions.

Thus, cathode rays are produced when the pressure is of the order of 0.01 mm of Hg.