# The Naked Scientists Forum

### Author Topic: Electrons!!  (Read 2500 times)

#### thegers91

• Jr. Member
• Posts: 19
##### Electrons!!
« on: 03/01/2008 13:15:21 »
The power output of a TV screen is 24W. If the accelerating voltage is 12000V, calculate the number of electrons striking the screen per second?

#### lyner

• Guest
##### Electrons!!
« Reply #1 on: 03/01/2008 14:32:46 »
Do you mean the power supplied to the electron gun is 24W?

#### lyner

• Guest
##### Electrons!!
« Reply #2 on: 03/01/2008 14:49:50 »
The energy of each electron hitting the screen will be
12000 electron volts
= 1.60217646 × 10^-19 X 1.2x10^4
= 1.9x10^-15 J
If the beam power is 24W, the number of electrons per second is
24/1.9x10^-15
=1.26x10^16

#### Pumblechook

• Hero Member
• Posts: 569
##### Electrons!!
« Reply #3 on: 03/01/2008 16:20:54 »
12 kV EHT  =  2 mA beam (Average?)  =  1.26×10e16 electrons

Amp is 6.24150948×10e18 Electrons/sec.
« Last Edit: 03/01/2008 16:22:44 by Pumblechook »

#### lyner

• Guest
##### Electrons!!
« Reply #4 on: 03/01/2008 18:11:15 »
Yes - I just like the electron volt. No need to work out the current.
You seem like a useful bloke with sums, Pumblechook- how about some profile?

#### The Naked Scientists Forum

##### Electrons!!
« Reply #4 on: 03/01/2008 18:11:15 »