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An electron falls from an energy level of -5.44eV to another energy level, E. If...

Physics
JAMB 2024

An electron falls from an energy level of -5.44eV to another energy level, E. If the emitted photon is of wavelength 5.68 x 10\(^{-6}\)m, calculate the energy change. [ Plank's constant = 6.63 x 10\(^{-34}\)Js, emitted radiation speed = 3.0 x 10\(^8\)ms\(^{-1}\)]

  • A. 1.49 x 10\(^{-20}\)J
  • B. 1.49 x 10\(^{-19}\)J
  • C. 3.49 x 10\(^{-20}\)J
  • D. 3.49 x 10\(^{-19}\)J
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Correct Answer: Option C
Explanation

Energy of the emitted photon(E) = \(\frac{\text{hc}}{\lambda}\)

\(\lambda\) = 5.68 x 10\(^{-6}\)m

h =  6.63 x 10\(^{-34}\)Js

c = 3.0 x 10\(^8\)ms\(^{-1}\)

E =\(\frac{(6.63\times 10^{-34}) \times (3.0 x 10^8)}{5.68\times 10^{-6}}\) = \(\frac{1.989\times 10^{-25}}{5.68\times 10^{-6}}\)

E = 3.50 x 10\(^{-20}\)J

Therefore, the energy change = 3.50 x 10\(^{-20}\)J

There is an explanation video available below.


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Explanation Video

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