discharge tubes!!?!!?!?! (1 Viewer)

[Validity]

why does higher pressure mean less current flow and no glow is emitted?
shouldn't there be a HUGE glow due to e- smashing and exciting the large amount of gas particles causing them to emit light?
the more e- deexciting , the more light emitted? isn't that how it works?

 

[Fizzy_Cyst]

High pressure = more gas particles = higher resistance. By definition, if resistance is higher, then current (flow of electrons/cathode rays) will decrease. If there are too many gas particles, then essentially it is an insulator and there will be no current/cathode rays at all

 

[Validity]

but how does the resistance IN THE TUBE affect the current coming from THE SOURCE OF POWER? and what happens with the glow?

 

[Fizzy_Cyst]

Current isnt coming from the source of power, it is the EMF (Voltage/Potential Difference) which is coming from the source of power and being applied to the electrodes. It is the resistance between the electrodes which determines the current. (I = V/R)

 

[Validity]

so should the glow increase or decrease?

 

[nightweaver066]

so should the glow increase or decrease?

At higher pressures, there may just be sparks jumping and at even higher, nothing will happen.

The electrons need to be able to accelerate after leaving the cathode (only possible with low pressure meaning minimal air molecules) and collide with air molecules to cause fluorescence (glow).