cathode ray tubes (1 Viewer)

[greecke]

in a cathode ray tube, which components focus the beam, control brightness and accelerate electrons along the tube?

A) heating filament
B) electrodes in the electron gun
C) deflection plates or coils
D) Flourescent screen

im sure its C but the answers i have been given says D

am i right???

 

[dawso]

ok nicolas efstathios, hav a think about it.....D? like, wtf?? therefore, the answer is C, but that doesnt make u right

 

[greecke]

thanks for that...its not my fault the stupid catholic teachers are wrong

 

[powerhouse]

I thought that was from the CSSA trial and they gave the answer as B when I answered C

 

[speed2]

I thought that was from the CSSA trial and they gave the answer as B when I answered C

the answer is (b) as the deflection plates control the position of the beam(X and Y), while the electrodes in the gun accelerate the electrons towards the screen. its not D for sure!

 

[helper]

The part has to do all three, and the only one that can be said to do all 3 is b.

A may have to do with brightness but has nothing to do with focus.
C has to do with focus but nothing to do with brightness or accelerating.
D has to do with brightness but nothing to do with focusing or accelerating.

B accelerates the charges with the potential difference, focuses by collimating and controls brightness by controlling the energy of the electrons.

 

[jarro_2783]

it's got to be b. c only deflects the electrons to direct them. The screen doesn't do anything except show where the electrons are hitting and the heating filament only releases electrons.

 

[kynanld]

It is definitly B.
the electron gun consists of 3 parts.
1. the filament (im not entirely sure but i think it controls brightness via how many electrons are produced... but this is differernt to what helper said so im prolly wrong) *brightness*
2. the negative cap (this has a negative charge and is used to focus and concentrate the beam with repulsive force) *focusing*
3. the anode (this has a positive charge and accelerates the electrons down the tube) *accelerates*

 

[helper]

Kynald, you probably have expressed it better than me.
The more electrons, the higher the current, the greater the energy supplied by the electron beam.

 

[great_guns]

its definately the electron gun

 

[Abtari]

Kynald, you probably have expressed it better than me.
The more electrons, the higher the current, the greater the energy supplied by the electron beam.

a bit off the q, but how does more electrons ensure a greater energy supplied by the electron beam?

 

[serge]

a bit off the q, but how does more electrons ensure a greater energy supplied by the electron beam?

it doesnt matter does it? isnt this in relation to CROs?
so more electrons is a higher intensity?

 

[helper]

As each electron hits the screen it passes on a photon of energy to the flourescing object. If you increase the number of electrons, you increase the number of photons, so increase the amount of energy.

 

[Abtari]

electrons are particles...how can they pass on photons....? they possess kinetic energy

 

[helper]

The KE that is absorbed and transmitted as light, is absorbed by electrons in the flourescing objects. The excitation of these electrons is quantised.