what is the acceleration of a proton in an electric field strength 4.0 x 10^4?

Question

How i did it }

F=MA
E=F/Q :F=QE

MA= QE : A=QE/M

using
mass 9.11x10^-31
charge 1.6x10^-19
Efs 4.0x10^4


and i get the answer 7.0x10^15

this is question 8 from physics pp edexcel ial jan 2014

mark scheme says the answer is supposed to be 3.8x10^12

i dont know what im doing wrong here

Answer 1

a = F/m = eE/m

 

You did not state the units of the electric field.  I will assume it is given in newtons/coulomb.

 

e = 1.6 x 10^-19 C

 

E = 4.0 x 10⁴ N/C

 

m = 1.67 x 10^-27 kg

 

a = (1.6 x 10^-19)(4.0 x 10⁴) / (1.67 x 10^-27) m/s² ≅ 3.83 x 10¹² m/s² 

Answer 2

You used the mass of an electron, not a proton.  The mass of a proton is 1.673 x 10^-27 kg.