Department of Pre-University Education, KarnatakaPUC Karnataka Science Class 12
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# Find the Energy, the Frequency and the Momentum of an X-ray Photon of Wavelength 0.10 Nm. - Physics

ConceptElectromagnetic Spectrum

#### Question

Find the energy, the frequency and the momentum of an X-ray photon of wavelength 0.10 nm.

(Use Planck constant h = 4.14 × 10-15 eVs, speed of light c = 3 × 108 m/s.)

#### Solution

Given:
Wavelength of the X-ray photon, λ = 0.1 nm
Speed of light, c = 3 xx 108 m/s

(a) Energy of the photon (E) is given by

E = (hc)/lambda

⇒ E = (1242  "eV")/0.1

⇒ E = 12420  "eV"

⇒ E = 12.42  "keV" ≈ 12.4  "keV"

(b) Frequency is given by

v = c/lambda

⇒v = (3 xx 10^8)/(0.1 xx 10^-9)

⇒v = 3 xx 10^18  "Hz"

(c) Momentum of the photon (P) is given by

P = E/c

⇒P = (12.4 xx 10^3 xx 1.6 xx 10^-19)/(3 xx 10^8)

⇒P = 6.613 xx 10^-24   "kg-m/s" ≈ 6.62 xx 10^-24  "g-m/s"

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Solution Find the Energy, the Frequency and the Momentum of an X-ray Photon of Wavelength 0.10 Nm. Concept: Electromagnetic Spectrum.
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