(a) A proton is released from rest and accelerates freely through a potential di

Question

(a) A proton is released from rest and accelerates freely through a potential difference* of size 150 V.
(*Note: You do not need to know the initial and final voltage values, only their difference!)

It will seek a lower  potential energy
by seeking a lower voltage

so its V will be: negative  

Also, what is its final speed?  m/s

(b) Repeat part a, but with an electron.
It will seek a lower potential energy
by seeking a  ---Select--- lower / higher N/A - wants to maintain  voltage
so its V will be: positive

Also, what is its final speed?  m/s

(c) Which particle gained more speed? proton / electron / N/A - they gained the same amount
Which particle gained more kinetic energy? N/A - they gained the same amount

Explanation / Answer

v = sqrt(2qV/m)

a)
v_Proton = sqrt((2*1.6*10^-19*150)/(1.67*10^-27))
= 1.7*10^5 m/s

b)
higher
v_electron = sqrt((2*1.6*10^-19*150)/(9.11*10^-31))
= 7.26*10^6 m/s

c)
Electron gained more speed.
KE = 1/2mv^2, so
KE_proton = 0.5*1.67*10^-27*(1.7*10^5)^2 = 2.4*10^-17 J
KE_electron = 0.5*9.11*10^-31*(7.26*10^6)^2 = 2.4*10^-17 J
So, N/A - they gained the same amount

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