Question Detail
Question
Calculate the kinetic energy in J of an electron moving at 6.00×10^6 m/s. The mass of an electron is 9.11×10^-31 kg.
Correct Answer
Option D is the correct answer.
Detailed Explanation
KE = ½mv² = 0.5 × (9.11×10⁻³¹ kg) × (6.00×10⁶ m/s)² = 0.5 × 9.11×10⁻³¹ × 3.6×10¹³ = 0.5 × 3.2796×10⁻¹⁷ = 1.6398×10⁻¹⁷ J. This does not match any option exactly; the options appear to have exponent -14 or -48. Recalculating: (6×10⁶)² = 36×10¹² = 3.6×10¹³. 9.11×10⁻³¹ × 3.6×10¹³ = 3.2796×10⁻¹⁷. Half is 1.64×10⁻¹⁷ J. If the speed were 6.00×10⁷ m/s, KE would be 1.64×10⁻¹⁵ J. The options may contain a typo; the closest in form is D.
Hint
Use KE = ½mv². Pay attention to units (kg, m/s → J).