- #1
chunkytuna21
- 37
- 0
An electron is initially at rest in a vacuum in a region where the potential is 0V. It is attracted by, and accelerates toward, a positively-charged metal plate at a potential of +12,000V. Assuming no other forces act on the electron, how fast is it moving when it hits the metal plate? Mass of electron is 9.1*10^-31kg
Delta PEe= qe(deltaV)...qe= 1.6*10^-19
KEi+PEi=KEf+PEf
KEf= PEi-PEf= -delta PE....because KEi is zero
1/2*m*vf^2= -qe(deltaV)
vf=[-2qe*deltaV/m]^1/2
Calculated PEe= (-1.6*10^-19)(12000)= -1.92*10^-15
Vf= [-2(-1.92*10^-15)/9.1*10^-31kg]^1/2= 6.50*10^7m/s
Final Answer: 6.50*10^7m/s
Is that correct? If not, where am I going wrong? Any help would be greatly appreciated.
Delta PEe= qe(deltaV)...qe= 1.6*10^-19
KEi+PEi=KEf+PEf
KEf= PEi-PEf= -delta PE....because KEi is zero
1/2*m*vf^2= -qe(deltaV)
vf=[-2qe*deltaV/m]^1/2
Calculated PEe= (-1.6*10^-19)(12000)= -1.92*10^-15
Vf= [-2(-1.92*10^-15)/9.1*10^-31kg]^1/2= 6.50*10^7m/s
Final Answer: 6.50*10^7m/s
Is that correct? If not, where am I going wrong? Any help would be greatly appreciated.