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# Physics De Broglie Equation watch

1. I don’t know how to work this question out??!! Help would be much appreciated.

Calculate the (a) speed and (b) wavelength of an electron which has been accelerated from rest through a Pd of 250 volts.

Thanks again
2. (Original post by Yodalam)
I don’t know how to work this question out??!! Help would be much appreciated.

Calculate the (a) speed and (b) wavelength of an electron which has been accelerated from rest through a Pd of 250 volts.

Thanks again

For (a), you need to use the conservation of energy.
Work done by the electric field in accelerating the electron = change in KE of the electron.

For (b), you need what you have named the title of the post - De Broglie Equation.
You have the speed in (a), which mean you can work out the momentum of electron and substitute it into the de Broglie relationship to obtain the wavelength.

I leave the working to you.
.
3. Got it, thanks

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