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GUJCET · Physics · Atoms

Ratio of radii of second and third orbits of H -atom is _________.

  1. A \(3: 2\)
  2. B \(2: 3\)
  3. C \(9: 4\)
  4. D \(4: 9\)
Verified Solution

Answer & Solution

Correct Answer

(D) \(4: 9\)

Step-by-step Solution

Detailed explanation

(D) \(4: 9\)
Radius \(r_{n} \propto \frac{n^{2}}{\mathrm{Z}}\)
But for H -atom \(\mathrm{Z}=1\)
\(\therefore \quad r_{n} \propto n^{2}\)
\(\therefore \quad \frac{r_{2}}{r_{3}}=\left(\frac{n_{2}}{n_{3}}\right)^{2}\)
\(\therefore \quad \frac{r_{2}}{r_{3}}=\left(\frac{2}{3}\right)^{2}\)
\(\therefore \quad \frac{r_{2}}{r_{3}}=\frac{4}{9}\)