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Homework Statement
Electrons are accelerated by a potential difference of 0.10 MV. Determine:
a) The mass an accelerated electron
b) The velocity of an accelerated electron
The mass of the electron has been successful determined, which I give here. I was doing wrong when I was counting the speed based on the rest mass of the electron. Here, I would like to be sure that qU = 0.5v^2 is correct based on the relativistic mass. I have problems in this course, because I get questions that I've never seen before.
Homework Equations
qU = mc^2 – m0c^2
qU = 0.5mv^2
The Attempt at a Solution
a)
100'000 V = 1.602*10^-14 Joule
m0c^2 = 8.18751672*10^-14 Joule
1.602*10^-14 = (8.18751672*10^-14) - mc^2
mc^2 = 9.78951672*10^-14
m = (9.78951672*10^-14) / c^2
m = 1.08917583*10^-30 kg
This far I know the relativistic mass is correct, easy task.
b)
I try to use the relativistic mass in this formula:
qU = 0.5mv^2
1.602*10^-14 = 0.5(1.08917583*10^-30)v^2
v^2 = 2.941673798*10^16
v = 171’513’084 m/s
Here, I’m not so sure that this is the right way. I only do believe so. I’m thankful for answers.