Pressure of a gas in discharge tube

In summary, when the pressure of the gas in a discharge tube is gradually lowered, a violet glow appears in the tube, the glow splits into bands which get further apart, and eventually the glow and bands disappear and are replaced by a green fluorescence. The possibility of the tube breaking into pieces is unlikely and unsupported by research. The phenomenon is explained by Paschen's Law, which describes the relationship between discharge and pressure in a gas.
  • #1
chikis
237
1

Homework Statement


When the pressure of the gas in a discharge tube is gradually lowered
I. There is a violet glow in the tube
II. The glow in the tube split into bands which get further apart
III. The glow and the bands eventually disappear and there is a green flourescence in the tube
IV. The tube breaks into pieces.
Which of the following are correct?
A. I and II only B. I and III only C. I and IV only D. I, II and III only E. I, II, III and IV only
I need explanation for your answers please! Any help will be so much appreciated. Thanks!


Homework Equations





The Attempt at a Solution


In my own view, if a gas must conduct electricity, it must do so on some certian conditions. A gas in a discharge tube will only conduct electricity through it, if high voltage is applied at the two terminals of the tube and that must be done maintaining the pressure of the gas at a low pressure. The colour of the glow in the tube depends on the nature of the gas inside the tube.

If the pressure of gas in the tube is continously lowered to the extent that there less molecule to ionize and cause flourecence in the tube,
then the stated conditions such as:

I. Violet glow in the tube
II. Glow in the tube spliting into bands which get further apart
III. Glow and the bands eventually disappearing and the emergence of green flourescence in the tube will be true.

But I doubt the last possibility, that is the possibility of the tube breaking into pieces. Because judging from all the googling I made on the Internet, I found nothing supporting the last possiblity. What do you viewers think?
 
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  • #2
chikis said:

Homework Statement


When the pressure of the gas in a discharge tube is gradually lowered
I. There is a violet glow in the tube
II. The glow in the tube split into bands which get further apart
III. The glow and the bands eventually disappear and there is a green flourescence in the tube
IV. The tube breaks into pieces.
Which of the following are correct?
A. I and II only B. I and III only C. I and IV only D. I, II and III only E. I, II, III and IV only
I need explanation for your answers please! Any help will be so much appreciated. Thanks!


Homework Equations





The Attempt at a Solution


In my own view, if a gas must conduct electricity, it must do so on some certian conditions. A gas in a discharge tube will only conduct electricity through it, if high voltage is applied at the two terminals of the tube and that must be done maintaining the pressure of the gas at a low pressure. The colour of the glow in the tube depends on the nature of the gas inside the tube.

If the pressure of gas in the tube is continously lowered to the extent that there less molecule to ionize and cause flourecence in the tube,
then the stated conditions such as:

I. Violet glow in the tube
II. Glow in the tube spliting into bands which get further apart
III. Glow and the bands eventually disappearing and the emergence of green flourescence in the tube will be true.

But I doubt the last possibility, that is the possibility of the tube breaking into pieces. Because judging from all the googling I made on the Internet, I found nothing supporting the last possiblity. What do you viewers think?

I think your answers are good. Here is more information about the discharge versus pressure -- it's called Paschen's Law (and the Paschen curve):

http://en.wikipedia.org/wiki/Paschen_curve

.
 
  • #3
berkeman said:
I think your answers are good. Here is more information about the discharge versus pressure -- it's called Paschen's Law (and the Paschen curve):

http://en.wikipedia.org/wiki/Paschen_curve

.

Thanks for the compliment!
 

1. What is the pressure of a gas in a discharge tube?

The pressure of a gas in a discharge tube refers to the amount of force that the gas exerts on the walls of the tube. It is measured in units of pascals (Pa) or atmospheres (atm).

2. How is the pressure of a gas in a discharge tube measured?

The pressure of a gas in a discharge tube can be measured using a pressure gauge or a manometer. These devices measure the force exerted by the gas on a known area and convert it to a pressure reading.

3. What factors affect the pressure of a gas in a discharge tube?

The pressure of a gas in a discharge tube is affected by the temperature, volume, and number of gas particles in the tube. As temperature and volume increase, so does the pressure. As the number of gas particles increases, the pressure also increases.

4. Why is the pressure of a gas in a discharge tube important?

The pressure of a gas in a discharge tube is important because it affects the behavior and properties of the gas. It can determine the rate of reactions, the solubility of gases, and the flow of gas through a system.

5. How is the pressure of a gas in a discharge tube related to the gas law?

The pressure of a gas in a discharge tube is related to the ideal gas law, which states that pressure is directly proportional to the number of gas particles and temperature, and inversely proportional to the volume of the gas. This relationship is expressed as P = nRT/V, where P is pressure, n is the number of moles of gas, R is the gas constant, T is the temperature, and V is the volume.

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