Q.
In Geiger-Marsden experiment, in a head-on collision between an α-particle and a gold nucleus, the minimum separation is 4×10−14m. The energy of α-particle is (Take, atomic number of gold =79 )
At distance of minimum separation, KE=PE. ⇒KE=rkZe⋅2e
or KE=4×10−14J9×109×79×2×(1.6×10−19)2 =4×10−14×1.6×10−199×109×79×2(1.6×10−19)2eV =5.688MeV(∵1MeV=1.6×10−13J)