Given below are two statements :
Statement I : Rutherford's gold foil experiment cannot explain the line spectrum of hydrogen atom.
Statement II : Bohr's model of hydrogen atom contradicts Heisenberg' uncertainty principle.
In the light of the above statements, choose the most appropriate answer from the options given below :

Solution

Chemistry ma’am · 4 steps

Judge each statement on its own: what Rutherford could not explain, and what Bohr claimed to know exactly.

1. Statement I. Rutherford's model has electrons orbiting the nucleus with no rule on which orbits or energies are allowed. It gives no reason for the electron to have only fixed energies, so it cannot explain why hydrogen emits only certain sharp lines. Statement I is true.
2. Statement II. Bohr's model puts the electron in a fixed circular orbit of exact radius, with an exact velocity. That means its position and momentum are both known precisely at the same time.

   Δ x · Δ p ≥ h/4π

3. Uncertainty check. Heisenberg says Δ x and Δ p cannot both be zero, because their product has a fixed lower limit. Bohr's exact orbits break this rule, so Statement II is true.
4. So. Both statements are true, which is option (d).

The idea to keep. Rutherford gave the nucleus but no fixed energy levels, so no line spectrum. Bohr gave fixed orbits, but an exact orbit means exact position and momentum together, which Heisenberg forbids.

Answer from the NTA final answer key. Solution by PrepWiser.