JEE Main2004PhysicsElectrostaticsActual
An -particle of energy 5 MeV is scattered through 180^ by a fixed uranium nucleus. The distance of the closest approach is of the order of
Options
- A1 Å
- B10⁻¹⁰ ~cm
- C10⁻¹² ~cm
- D10⁻¹⁵ ~cm
Correct answer
C. 10⁻¹² ~cm
Step-by-step solution
At closest approach, all the kinetic energy of the -particle will converted into the potential energy of the system, K.E. = P.E. aligned & 5 MeV = 1 4 ₀ q ₁ q ₂ r & 5 10^6 e =9 10^9 Z ₁ Z ₂ e ^2 r & r = 9 10^9 92 2 1.6 10⁻¹⁹ 5 10^6 & r =5.3 10⁻¹⁴ ~m =5.3 10⁻¹² ~cm aligned