JEE PYQ: Atomic Physics Question 40
Question 40 - 2020 (08 Jan Shift 1)
The graph which depicts the results of Rutherford gold foil experiment with $\alpha$-particles is:
$\theta$: Scattering angle, Y: Number of scattered $\alpha$-particles detected
(1) Y starts high and decreases as a curve toward $\pi$
(2) Y increases sharply near $\pi$
(3) Y starts high, dips, then rises
(4) Y is relatively flat then drops
Show Answer
Answer: (4)
Solution
As per Rutherford $\alpha$-particle scattering experiment, number of $\alpha$-particles scattered (N) related with deflection angle $\theta$ as $N \propto \frac{1}{\sin^4(\theta/2)}$. The corresponding Y versus $\theta$ graph shows a steep decrease from high values at small angles.
BETA
