WAEC Physics 2023 Objective — Question 3
Question 3 of 50 from the West African Examinations Council (WAEC) Physics 2023 Objective paper, with the correct answer and a full explanation.
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An electron moves from an energy level of -8.6 eV to another level of -3.5 eV. Determine the frequency of the absorbed radiation. [1eV=1.6×10⁻¹⁹J, h=6.6×10⁻³⁴Js]
- A. 1.24×10¹⁵ HzCorrect
- B. 2.93×10¹⁵ Hz
- C. 3.59×10¹⁶ Hz
- D. 5.39×10¹⁶ Hz
Explanation
ΔE = E₂-E₁ = -3.5eV-(-8.6eV) = 5.1eV = 8.16×10⁻¹⁹J. f = ΔE/h = 8.16×10⁻¹⁹/6.6×10⁻³⁴ = 1.24×10¹⁵ Hz.
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