Question
What is the impact parameter? Explain the trajectory of $\alpha$-particle from it.
✓
Answer
→Impact parameter (b) : "The perpendicular distance of the initial velocity vector of the $\alpha$-particle from the centre of the nucleus is called the impact parameter."
→The path (trajectory) of an $\alpha$-particle depends on impact parameter of the collision with the nucleus.
→As shown in the figure, the impact parameters (b) of $\alpha$-particles are different so that they scattered in various directions with different probabilities.
→An $\alpha$-particle which is close to the nucleus suffers large scattering.
→In case of head-on collision, the impact parameter is minimum and the $\alpha$-particle rebounds back. (For head-on collision $b \approx 0, \theta \approx 180^{\circ}$ )
→For a large impact parameter, the $\alpha$-particle goes nearly undeviated and has a small deflection.
→ The fact that only a small fraction of the number of incident particles of the number of incident particles rebound back indicates that the number of $\alpha$-particles undergoing head on collision is small. This implies that the mass and positive charge of the atom is concentrated in a small volume.
→Therefore, Rutherford scattering experiment is a powerful way to determine the size of the nucleus.
→The path (trajectory) of an $\alpha$-particle depends on impact parameter of the collision with the nucleus.
→As shown in the figure, the impact parameters (b) of $\alpha$-particles are different so that they scattered in various directions with different probabilities.
→An $\alpha$-particle which is close to the nucleus suffers large scattering.
→In case of head-on collision, the impact parameter is minimum and the $\alpha$-particle rebounds back. (For head-on collision $b \approx 0, \theta \approx 180^{\circ}$ )
→For a large impact parameter, the $\alpha$-particle goes nearly undeviated and has a small deflection.
→ The fact that only a small fraction of the number of incident particles of the number of incident particles rebound back indicates that the number of $\alpha$-particles undergoing head on collision is small. This implies that the mass and positive charge of the atom is concentrated in a small volume.
→Therefore, Rutherford scattering experiment is a powerful way to determine the size of the nucleus.
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