JEE Main 2026 — Atomic Physics Question with Solution
JEE Main 2026 (04 April Shift 2)
Question
In Rutherford's alpha-particle scattering experiment, only a few alpha particles rebound back because
A. The size of gold nucleus is very small as compared to the size of gold atom.
B. Alpha particle and gold nucleus have equal charge.
C. The impact parameter is minimum for a few alpha particles.
D. A few alpha particles have very high kinetic energy.
E. Only a few alpha particles undergo head-on collision with the nuclei.
Choose the correct answer from the options given below:
A. The size of gold nucleus is very small as compared to the size of gold atom.
B. Alpha particle and gold nucleus have equal charge.
C. The impact parameter is minimum for a few alpha particles.
D. A few alpha particles have very high kinetic energy.
E. Only a few alpha particles undergo head-on collision with the nuclei.
Choose the correct answer from the options given below:
Choose an option
Show full solutionCorrect option: D
Correct answer
DA, C, E Only
Step-by-step explanation
In Rutherford's alpha-particle scattering experiment, the rebounding of alpha particles (scattering angle ) occurs when they undergo a head-on collision with the gold nucleus.
A head-on collision corresponds to an impact parameter close to zero. Since the size of the gold nucleus ( m) is extremely small compared to the size of the gold atom ( m), the effective target area is very small. Consequently, the probability of an alpha particle having a minimum impact parameter is very low.
Thus, only a few alpha particles undergo head-on collisions and rebound back. This makes statements A, C, and E correct.
Statement B is incorrect because the charge of an alpha particle is while the charge of a gold nucleus is .
Statement D is incorrect because the alpha particles emitted from the radioactive source have nearly the same kinetic energy.
Answer: A, C, E Only
A head-on collision corresponds to an impact parameter close to zero. Since the size of the gold nucleus ( m) is extremely small compared to the size of the gold atom ( m), the effective target area is very small. Consequently, the probability of an alpha particle having a minimum impact parameter is very low.
Thus, only a few alpha particles undergo head-on collisions and rebound back. This makes statements A, C, and E correct.
Statement B is incorrect because the charge of an alpha particle is while the charge of a gold nucleus is .
Statement D is incorrect because the alpha particles emitted from the radioactive source have nearly the same kinetic energy.
Answer: A, C, E Only
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This is a previous-year question from JEE Main 2026, covering the Atomic Physics chapter of Physics. PrepSharp catalogues every PYQ from JEE Main with a verified answer key and step-by-step solution prepared by IIT alumni — so you can search by chapter, topic or year and revise efficiently.