Modern Physics practice focused on photoelectric effect, atomic models, spectra, nuclei and radioactivity. Every preview below comes from NeetVellum's live original bank—not an unverified PYQ reconstruction.
photoelectric effect, atomic models, spectra, nuclei and radioactivity.
Original practice preview
These are current-syllabus NeetVellum questions, shown separately from historical-paper provenance.
Example 1 · difficulty 1/5
In a Geiger-Marsden type α-particle scattering experiment on a thin gold foil, it is observed that only about 1 in every 8000 α-particles is deflected through an angle greater than 90°. The most direct conclusion drawn from this rare large-angle scattering is that:
A. the electrons of the atom carry most of its mass
B. the atom as a whole is electrically neutral
C. nearly all the mass and the entire positive charge of the atom are concentrated in a tiny central region
D. α-particles are strongly attracted by the orbital electrons
Example 2 · difficulty 3/5
An α-particle with kinetic energy 5.0 MeV approaches a gold nucleus (Z = 79) head-on. Ignoring recoil, the distance of closest approach is approximately:
A. 2.3 × 10⁻¹⁴ m
B. 4.55 × 10⁻¹⁴ m
C. 9.1 × 10⁻¹⁴ m
D. 4.55 × 10⁻¹⁵ m
Example 3 · difficulty 2/5
According to the Bohr model, the radius of the first orbit of the He⁺ ion is:
A. 0.265 Å
B. 0.529 Å
C. 1.058 Å
D. 2.116 Å
The evidence-first practice loop
1. Verify provenanceOfficial paper and final key before accepting a PYQ label.
2. Attempt closed-bookExpose the concept or execution gap before rereading.
3. Repair and returnClassify the miss and re-practice after a delay.