Q.

In an alpha particle scattering experiment distance of closest approach for the α particle is 4.5×10-14m. If target nucleus has atomic number 80, then maximum velocity of α-particle is ________ ×105m/s approximately.

(14πε0=9×109 SI unit, mass of α particle = 6.72×10-27 kg)          [2024]


Ans.

(156)             KQqrmin=12mv2v=2K(Ze)·(2e)qmrmin=4KZe2mrmin

                     v=4×9×109×80×(1.6×10-19)26.72×10-27×4.5×10-14

                     =1.56×107m/s=156×105m/s