Question

Assertion : The characteristics of cathode rays do not depend upon the material of electrodes and the nature of the gas present in the cathode ray tube.
Reason: Cathode rays consist of negatively charged particles, called electrons.

• A. If both assertion and reason are true and reason is the correct explanation of assertion.
• B. If both assertion and reason are true but reason is not the correct explanation of assertion.
• C. If assertion is true but reason is false.
• D. If both assertion and reason are false.

Answer 1

Answer: (B)

Characteristics of cathode rays are:
(i) The cathode rays start from the cathode and move towards the anode.
(ii) These rays themselves are not visible but their behaviour can be observed with the help of phosphor materials such as $ZnS$.
(iii) In the absence of an electrical field or magnetic field, these rays travel in straight lines.
(iv) In the presence of the electrical or magnetic field, the behaviour of cathode rays will be similar to that expected from negatively charged particles.
(v) The characteristics of cathode rays i.e. electrons don't depend upon the material of electrodes.
Thus both assertion and reasons are correct but the reason is not the explanation of the assertion.