Naked Science Forum

Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: IzzieC on 15/05/2018 18:33:13

Title: Ion or electron: Which has more energy?
Post by: IzzieC on 15/05/2018 18:33:13
Roshan asks:

"If an electron and an ion are exposed to the same potential, which will have more energy?"

Can you help?
Title: Re: Ion or electron: Which has more energy?
Post by: PmbPhy on 15/05/2018 19:08:12
Roshan asks:

"If an electron and an ion are exposed to the same potential, which will have more energy?"

Can you help?
The one with the greater charge. Also the more positive the ion is he larger the potential energy
Title: Re: Ion or electron: Which has more energy?
Post by: evan_au on 15/05/2018 22:42:51
The electron has a charge of -1. Let's assume that the ion has a charge of +1 (or -1), so they balance.

If you accelerate the electron and the ion in a vacuum, and allow them to "fall" through a Potential Difference of 1 Volt (abbreviation: 1V), both the electron and the ion will have gained an energy of 1 electron-Volt (abbreviation: 1 eV).

However, the electron is at least 1800 times lighter than the ion, so the velocity of the electron will be much higher than the ion for the same energy, according to the equation E=mv2/2
- Where E is the energy of the ion or electron (1 eV in the example)
- m is the mass of the ion or electron
- v is the velocity of the ion or electron

In practise, voltages to accelerate electrons and ions are often much higher than 1 Volt - perhaps 50,000V in an X-Ray machine, and (with some tricks using microwaves), the Large Hadron Collider makes the protons "feel" like they have been exposed to a potential difference of trillions of volts.