In a Rutherford scattering experiment when a projectile of charge Z₁ and mass M₁ approaches a target nucleus of charge Z₂ and mass M₂, the distance of closest approach is r. The energy of the projectile is

Options

(a) directly proportional to Z₁ Z₂
(b) inversely proportional to Z₁
(c) directly proportional to mass M₁
(d) directly proportional to M₁ x M₂

Correct Answer:

directly proportional to Z₁ Z₂

Explanation:

The kinetic energy of the projectile is given by
1/2 mv² = Ze (2e) / 4π?￢ﾂﾀr₀
= Z₁ Z₂ / 4π?￢ﾂﾀr₀
Thus energy of the projectile is directly proportional to Z₁, Z₂.