AIPMT 2010 Physics and Chemistry Paper

At the distance of closest approach d, Kinetic energy = Potential energy
‌

1

2

mv2=‌

1

4πε0

‌

(2e)(Ze)

r0

where,
Ze= charge of target nucleus
2e= charge of alpha nucleus
‌

1

2

mv2= kinetic energy of alpha nucleus of mass m moving with velocity v
or ‌‌d=‌

2Ze2

4πε0(‌ 1 2 mu2)

‌‌∴‌‌d∝‌

1

m