is the wavelength of a photon of energy 35 keV. (Take h = 6.625×10⁻³⁴ J s, c = 3×10⁸ m s⁻¹ and 1 eV = 1.6×10⁻¹⁹ J.)

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Accepted Answer

(1) 35×10⁻¹² m. Given: E = 35 keV = 35×10³×1.6×10⁻¹⁹ = 5.6×10⁻¹⁵ J. Idea: for a photon E = (hc)/λ, so λ = (hc)/E. hc = 6.625×10⁻³⁴×3×10⁸ = 1.9875×10⁻²⁵ J m λ = (1.9875×10⁻²⁵)/(5.6×10⁻¹⁵) = 3.55×10⁻¹¹ m This is 35.5×10⁻¹² m, about 0.355 A: an X-ray wavelength. So λ ≈ 35×10⁻¹² m.

______ is the wavelength of a photon of energy 35 keV. (Take h = 6.625×10⁻³⁴ J s, c = 3×10⁸ m s⁻¹ and 1 eV = 1.6×10⁻¹⁹ J.)

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Why the other options are wrong