physics
posted by chandankumar on .
if electron are caused to fall through a potential difference of 100000 voltage , determine their final speed if they were initially at rest.

e*100,000 is the kinetic energy.
e is the electron charge,1.6*10^19 C
Set 100,000*e equal to (1/2)mV^2 and solve for V
m is the electron mass. 
6646

p.d.=100000V
therefore, workdone , W=q×p.d.
W=1.6×10^19 × 100000
=1.6×10^14 Joules
since work done = force × displacement
F×s=1.6×10^14
m×a×s=1.6×10^14
9.1×10^31×a×s=1.6×10^14
a×s=(1.6×10^14)÷(9.1×10^31)
a×s=1.75×10^17
v^2/2=1.75×10^17
v=5.09×10^8m/s