Determining the charge or mass of an electron

[katherine]

I have to design an experiment that determines either the charge or mass of a single electron, something like was millikan did, for under $500 give or take a bit. We have some equipment, but not much, already. The design has to be innovative and doesn't have to be, or shouldn't be, exactly like millikan's experiment. Any ideas?

[dlgoff]

I have to design an experiment that determines either the charge or mass of a single electron, something like was millikan did, for under $500 give or take a bit. We have some equipment, but not much, already. The design has to be innovative and doesn't have to be, or shouldn't be, exactly like millikan's experiment. Any ideas?

It occured to me that you can find the e/m ratio using Thomson's apparatus. Do you have a CRT you could use?

Don

[katherine]

I was thinking that I could use something like coloumb's experiment. I was thinking that I would suspend two masses from a rod then induce a like charge in each. Then somehow from their deflection could I calculate the charge? Would I have to use pendulum properties to carry through with this?

[dlgoff]

I was thinking that I could use something like coloumb's experiment. I was thinking that I would suspend two masses from a rod then induce a like charge in each. Then somehow from their deflection could I calculate the charge? Would I have to use pendulum properties to carry through with this?



Yes and yes. When the displacement is in equilibrium, the electrical force equals the gravational force . Use columb's law and newton's law.

[chroot]

Could you build a miniature mass spectrometer?

- Warren

[nautica]

So electrons are considered to have mass?????

Nautica

[HallsofIvy]

originally posted by nautica
So electrons are considered to have mass?????
That seems a strange question! Yes, of course, electrons are not only "considered" to have mass, they have mass that has been accurately measured at about 9.1x 10-31kg.

[nautica]

Originally posted by HallsofIvy
That seems a strange question! Yes, of course, electrons are not only "considered" to have mass, they have mass that has been accurately measured at about 9.1x 10-31kg.

I guess I am confused. I was under the assumption that electrons act as waves and were actually a point of zero mass??? Enlighten me, please.

Thanks
Nautica

[dlgoff]

I guess I am confused. I was under the assumption that electrons act as waves and were actually a point of zero mass??? Enlighten me, please.

You might be thinking of photons. They are point particles with no mass. They are the carrier of the electromagnetic force determined by electrons, which are also point particles but have mass.