JEE Advanced 2012 Paper 1 Physics Q20

Physics · Dual Nature of Radiation & Matter · Electrostatic Potential & Capacitance

Problem

A proton is fired from very far away towards a nucleus with charge

Q=120e

, where

e

is the electronic charge. It makes a closest approach of

10\,\mathrm{fm}

to the nucleus. The de Broglie wavelength (in units of fm) of the proton at its start is: (take the proton mass,

m_p=(5/3)\times10^{-27}\,\mathrm{kg}

;

h/e=4.2\times10^{-15}\,\mathrm{J\,s/C}

;

1/(4\pi\varepsilon_0)=9\times10^9\,\mathrm{m/F}

;

1\,\mathrm{fm}=10^{-15}\,\mathrm m

)