Solving for a characteristic wavelength?

An electron is accelerated through an electric potential to a kinetic energy of 18.9 keV or 3.02811351*10^-15 joules What is its characteristic wavelength? [Hint: Recall that the kinetic energy of a moving object is E = (1/2)m(v^2)] So i first tried solving the problem by solving for v: 3.02811351*10^-15 =... show more An electron is accelerated through an electric potential to a kinetic energy of 18.9 keV or 3.02811351*10^-15 joules
What is its characteristic wavelength? [Hint: Recall that the kinetic energy of a moving object is E = (1/2)m(v^2)]

So i first tried solving the problem by solving for v: 3.02811351*10^-15 = (1/2)m(v^2) where m is the mass of an electron which is 9.11 x10^-31.
Then i used λ = hv/E to solve for λ where h is 6.626*10^-34 v is the velocity that i solved for an E is 3.02811351*10^-15 J
Is this the correct way because i got a wrong answer, what am i doing wrong? Thanks
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