Question

Deflection of the cathode rays produced in discharge tube in presence of external electric field is represented by the given diagram.
Identify the correct statement for the following system.

• A. Upper terminal is positive terminal
• B. Lower terminal is positive terminal
• C. Lower terminal is negative terminal
• D. Can not be predicted

Answer 1

The correct option is B Lower terminal is positive terminal

In presence of elctric field, the behaviour of cathode rays is
similar to that expected of negatively charged particles. Therefore, the deflection of cathode rays will be observed towards the positive terminal which is the lower terminal in the given diagram.