9. Proton, electron, neutron, and alpha particles have the same momentum. Which of them has the highest kinetic energy (KE)?(Work, Power & Energy, law of conservation of energy)
Correct answer: B. Electron
- A. Proton
- B. Electron
- C. Neutron
- D. Alpha particle
Explanation
Explanation: Kinetic energy (KE) is given by KE = 1/2 mv², where m is mass and v is velocity. Since all particles have the same momentum (p = mv), the one with the smallest mass (electron) will have the highest velocity and therefore the highest KE.Incorrect Options:(a) While protons are heavier than electrons, they also have lower velocities due to the same momentum. This leads to lower KE compared to electrons.(c) Similar to protons, neutrons have higher mass but lower velocities, resulting in lower KE than electrons.(d) Alpha particles are much heavier than electrons, but their lower velocities due to the equal momentum translate to lower KE compared to electrons.
Last updated
About Work and Energy
Work transfers energy when a force causes displacement, while kinetic energy, gravitational potential energy and power describe motion, position and the rate of energy transfer. The work-energy theorem links net work with change in kinetic energy, and efficiency accounts for energy losses rather than treating them as energy destruction.
Practise Work and Energy
748 free Work and Energy MCQs from Physics, each with the correct answer and an explanation. Unlimited attempts, no account needed.
Exams that ask Physics questions like this
Physics is on 13 papers prepared for on TestUstad, and all of them draw the same bank, so this question is worth knowing for every one of them.