If the kinetic energy of an electron is 100 eV, what is the wavelength of the de-Broglie wave associated with it? [h = 6.6 x 10\(^{-34}\) J s, e = 1.6 x 10\(^{-19}\)C, m\(_{e}\), = 9.1 x 10\(^{-31}\) kg]
1.22 x 10\(^{-10}\)m
4.10 x 10\(^{-10}\)m
3.90 x 10\(^{-10}\)m
5.50 x 10\(^{-14}\)m
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Discussions (8)

The selected answer is wrong.The correct answer is option A, 1.22× 10^-10m not 'D'
The k.E of the electron is 100eV meaning you are supposed to convert it to joules by multiplying it with 1.6×10^-19.
That is Ke = 100x1.6x10^-19

λ = h/p = λ/mv
K.E = 1/2mv²
how is λ = h/√2×m×K.E?🤨
because mv² = 2K.E
still wondering how my school got the formula

WAEC 2022 Physics objectives question 33 the selected answer is wrong.The correct answer is 1.22× 10^-10m ie 'A' not 'D'
The k.E of the electron 100eV suppose to be converted to joules by multiplying it with 1.6×10^-19.

