Question

In the discharge tube, cathode rays are found to move along a straight line path. This is possible when:

• A. an electric field alone is present
• B. a magnetic field alone is present
• C. both electric and magnetic fields are present in same direction
• D. both electric and magnetic fields are present along perpendicular directions

Answer 1

The correct option is A an electric field alone is present

In discharge tube, cathode says are found to move along a straight line path when only electric filed is present. Cathode rays are accelerated electrons moving away from a cathode to a anode. In the presence of both electric and magnetic field, cathode rays can be bent. For example in presence of both electric and magnetic field, deflection coils in cathode ray tubes can bend electron beams.