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The emission spectrum of cesium contains two lines whose frequencies are (a) 3.45 × 10¹4 Hz and (b) 6.53 × 10¹4 Hz. What are the wavelengths and energies per photon of the two lines? What color are the lines?

a) Wavelength and energy for line (a)
b) Wavelength and energy for line (b)
c) Color of line (a)
d) Color of line (b)

User Kenyee
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Final answer:

The wavelength and energies per photon for the cesium lines at frequencies 3.45 × 10¹⁴ Hz and 6.53 × 10¹⁴ Hz are 870 nm (infrared, non-visible) and 460 nm (blue), and their energies are 2.286 × 10⁻¹⁹ J and 4.326 × 10⁻¹⁹ J respectively.

Step-by-step explanation:

To determine the wavelength (λ) and energy per photon of the cesium emission lines, we can use the speed of light equation c = λf, where c is the speed of light (3.00 × 108 m/s) and f is the frequency of the light. The energy per photon can be calculated using the energy equation E = hf, where h is Planck's constant (6.626 × 10-34 J·s).

a) For line (a) with the frequency of 3.45 × 1014 Hz:

  • Wavelength (λ) = c/f = (3.00 × 108 m/s) / (3.45 × 1014 Hz) ≈ 8.70 × 10-7 meters or 870 nm.
  • Energy (E) = hf = (6.626 × 10-34 J·s) × (3.45 × 1014 Hz) ≈ 2.286 × 10-19 joules per photon.

b) For line (b) with the frequency of 6.53 × 1014 Hz:

  • Wavelength (λ) = c/f = (3.00 × 108 m/s) / (6.53 × 1014 Hz) ≈ 4.60 × 10-7 meters or 460 nm.
  • Energy (E) = hf = (6.626 × 10-34 J·s) × (6.53 × 1014 Hz) ≈ 4.326 × 10-19 joules per photon.

c) The color of line (a) with a wavelength of 870 nm falls into the infrared range and therefore would not be visible to the human eye.

d) The color of line (b) corresponds to a wavelength of 460 nm, which is typically associated with a blue hue.

User Kkkkk
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