- #1
bry
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Homework Statement
Ok so we have been given a diagram of a cathoe ray tube, with relevant data on it. The second question asks to "calculate the speed of the electron, using data from the first question". I need to make sure the answer is correct as it leads into many different questions.
I am unable to attach the picture, but here are all details:
Distance between metal plates: 5cm
Length of metal plates: 10cm
Charge on upper plate: 500V
No charge on lower plate
Charge on anode: 1000V
Homework Equations
The first question was to calculate the kinetic energy gained by an electron traveling from cathode to anode. What i calculated was:
E_k=qV=C×V
-1.6×〖10〗^(-19)×1000
E_k=-1.6×〖10〗^(-16) N
The Attempt at a Solution
I used two different methods to work this out, but got two different answers:
F=E_k
E_k=1/2 mv^2
v=√((2×E_k)/m)
v=√((2×-1.6×〖10〗^(-16))/(9.11×〖10〗^(-31) ))
v=-1.87 〖ms〗^(-1)
OR
s=((2×C×V))/m
s=((2×-1.6×〖10〗^(-16)×500))/(9.11×〖10〗^(-31) )
s= -1.76 〖ms〗^(-48)