Proton, electron, neutron and α-particle have same momentum. Which of them have highest K.E?
Correct answer: B. Electron
- A. Proton
- B. Electron
- C. Neutron
- D. α-particle
Explanation
First, write the equation of kinetic energy in terms of momentum. K.E = 1/2 mv2 = m2v2/2m = P2/2m as p=mv so, p2 = m2v2 K.E = P2/2m the momentum for all particles is the same. So, we can differentiate the kinetic energy on the basis of mass. K.E. has an inverse relation with mass. So, the particle with the smallest mass will have the greatest K.E. As the molar mass of proton = 1, neutron = 1, alpha particle = 4, and electron = 1/1837.
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