WAEC Physics 2017 Objective — Question 46
Question 46 of 50 from the West African Examinations Council (WAEC) Physics 2017 Objective paper, with the correct answer and a full explanation.
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An electron moves with a speed of 2.0x10⁶ ms⁻¹ in a straight line. Calculate the wavelength of the electron wave. [mass of an electron=9.1x10⁻³¹kg] [Planck's constant=6.6x10⁻³⁴Js]
- A. A. 3.63x10⁻¹⁰mCorrect
- B. B. 6.51x10⁻⁹m
- C. C. 4.24x10⁻⁸m
- D. D. 7.25x10⁻¹⁰m
Explanation
Using de Broglie's equation, λ=h/mv = 6.6x10⁻³⁴/(9.1x10⁻³¹x2x10⁶) = 3.63x10⁻¹⁰m.
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