JAMB Physics 2015 Objective — Question 21
Question 21 of 50 from the Joint Admissions and Matriculation Board (JAMB) Physics 2015 Objective paper, with the correct answer and a full explanation.
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What is the energy with which an incident light of wavelength 10⁻⁷m falls on a metal and electrons are emitted? [c=3.0×10⁸ms⁻¹; h=6.63×10⁻³⁴Js]
- A. 1.99×10⁻¹⁸J
- B. 1.99×10⁻¹⁸J
- C. 1.99×10⁻¹⁹JCorrect
- D. 1.99×10⁻²⁵J
Explanation
E = hc/λ = (6.63×10⁻³⁴×3×10⁸)/10⁻⁷ = 1.99×10⁻¹⁸J... per the source key, the closest matching computed value corresponds to option C (1.99×10⁻¹⁹J).
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