Electron gun

Question 1

What does an electron gun do, simple terms.

Answer 1

Electron gun produces a narrow beam of electrons through a vacumn

Question 2

How does an electron gun work?

4 steps

Answer 2

1. Metal filament is heated up via electric current
2. Electrons on surface of metal filament gain kinetic energy from thermal energy
3. Some electrons have enough kinetic energy to escape surface of metal filament. - Called thermionic emissions
4. The electrons accelerate towards anode because there is a change in PD between filament and anode.
   And they pass through a hole in anode.

Question 3

what is the equation of finding the electron’s speed in an electron gun?

Answer 3

Work is done on electrons and this is also same as kinetic energy.

so work done = kinetic energy

eV = 0.5mv^2

Where e = charge of the electron = 1.6 x 10^-19

V = voltage

m = mass of electron which no change = 9.11 x 10^-31

rearrange for V which is velocity in ke equation.

Question 4

Mass of electron

Answer 4

9.11x10^-31

Question 5

value for charge of electron

Answer 5

1.6x10^-19