NEET (UG)

Practice Test 1 — Atoms & Nuclei

12 questions • 18 minutes • auto-graded with full solutions

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Section A — MCQ (Single Correct)

Question 1

Rutherford's alpha-scattering experiment discovered the:

Solution: It revealed the atomic nucleus.

Question 2

The energy of the ground state of hydrogen is:

Solution: $E_1 = -13.6\ \text{eV}$.

Question 3

The Balmer series of hydrogen lies in the:

Solution: Balmer ($n_f = 2$) is visible.

Question 4

The nuclear radius is proportional to:

Solution: $R = R_0 A^{1/3}$.

Question 5

Binding energy per nucleon is maximum near:

Solution: Peak near iron ($A \approx 56$).

Question 6

After 2 half-lives, the fraction of a radioactive sample remaining is:

Solution: $(1/2)^2 = 1/4$.

Question 7

$1\ \text{u}$ corresponds to an energy of:

Solution: $1\ \text{u} = 931.5\ \text{MeV}$.

Question 8

Energy is released in fusion when:

Solution: Light nuclei joining release energy (toward the BE peak).

Section B — Assertion & Reason

Question 9

A: The hydrogen spectrum consists of discrete lines rather than a continuous band.
R: The energy levels of the electron in a hydrogen atom are quantised.

Solution: Quantised levels allow only certain transition energies, giving discrete lines — R explains A.

Question 10

A: The density of nuclear matter is nearly the same for all nuclei.
R: The nuclear radius is proportional to $A^{1/3}$, so volume is proportional to $A$.

Solution: Volume $\propto A$ with mass $\propto A$ gives constant density — R explains A.

Question 11

A: Alpha particles have greater penetrating power than gamma rays.
R: Gamma rays are uncharged high-energy photons.

Solution: Gamma rays penetrate far more than alpha particles, so A is false; R correctly describes gamma rays.

Question 12

A: Energy is released in the fission of a heavy nucleus.
R: The binding energy per nucleon of the fragments is greater than that of the original nucleus.

Solution: Higher BE/nucleon in the products means energy is released — R explains A.