Which one of the following statements regarding cathode rays is not correct?

examrobotsa's picture

Submitted by examrobotsa on

Q: (NDA-II/2019)

Which one of the following statements regarding cathode rays is not correct?

question_subject: 

Science

question_exam: 

NDA-II

stats: 

0,5,15,6,5,7,2

keywords: 

{'cathode rays': [0, 0, 0, 3], 'cathode ray particles': [0, 0, 0, 1], 'cathode ray tubes': [0, 0, 0, 1], 'cathode': [0, 0, 0, 1], 'electrons': [0, 0, 0, 5], 'anode': [0, 0, 0, 3], 'television picture tubes': [0, 0, 0, 2], 'magnetic fields': [0, 0, 0, 3], 'straight lines': [0, 0, 0, 1]}

Option 1 states that cathode ray particles are electrons, which is correct. Cathode rays are actually streams of electrons that are emitted from the cathode (negative electrode) in a vacuum tube.

Option 2 states that cathode ray particles start from the anode (positive electrode) and move towards the cathode. This statement is incorrect. In a cathode ray tube, electrons are emitted from the cathode and accelerated towards the anode due to the electric field created between the electrodes.

Option 3 states that in the absence of electrical and magnetic fields, cathode rays travel in straight lines, which is correct. Cathode rays have been observed to travel in straight lines in the absence of external electric and magnetic fields.

Option 4 states that television picture tubes are cathode ray tubes, which is correct. Cathode ray tubes are commonly used in television displays to produce images by directing electron beams onto a phosphorescent screen.

In conclusion, option 2 is the statement that is not correct.