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multiple choice question - momentum/particle physics

An electron gun uses a potential difference to accelerate electrons from rest to a speed of 2.00×10^7 ms–1.
The potential difference is
A 569 V
B 1140 V
C 2280 V
D 4560 V

Thankyouu

Reply 1

usycool1

Original post by pureandmodest

An electron gun uses a potential difference to accelerate electrons from rest to a speed of 2.00×10^7 ms–1.
The potential difference is
A 569 V
B 1140 V
C 2280 V
D 4560 V

Thankyouu

Potential difference is work done per unit charge.

Calculate the work done.
Divide by the charge of an electron.

Make sense? :smile:

Reply 2

pureandmodest

Original post by usycool1

Potential difference is work done per unit charge.

Calculate the work done.
Divide by the charge of an electron.

Make sense? :smile:

how do i work out the work done :c?
sorry, physics isn't my strong point

Reply 3

Stonebridge

Original post by pureandmodest

An electron gun uses a potential difference to accelerate electrons from rest to a speed of 2.00×10^7 ms–1.
The potential difference is
A 569 V
B 1140 V
C 2280 V
D 4560 V

Thankyouu

You need the mass of the electron from your data sheet or from the question.
Work out its kinetic energy from the speed it attains.

A charge q moving through a pd of V volts gains Vq amount of energy.

Combine these two ideas to find V. (You know q for the electron.)