JAMB Physics 2009 Objective — Question 45
Question 45 of 50 from the Joint Admissions and Matriculation Board (JAMB) Physics 2009 Objective paper, with the correct answer and a full explanation.
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45. If electrons are accelerated from rest through a potential difference of 10kV, what is the wavelength of the associated electron? [mₑ=9.1x10⁻³¹kg, e=1.6x10⁻¹⁹C, h=6.6x10⁻³⁴Js]
- A. 1.22x10⁻¹⁰mCorrect
- B. 3.87x10⁻¹¹m
- C. 2.27x10¹¹m
- D. 6.93x10⁻¹¹m
Explanation
E=qV=1.6x10⁻¹⁵J. v=√(2E/m)≈5.93x10⁷m/s. λ=h/mv≈1.22x10⁻¹⁰m.
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