NEET Atoms and Nuclei — Set 1

Question 1

Which of the following statements is incorrect about Rutherford’s nuclear model?

Accepted Answer

Rutherford’s model does not explain atomic stability, as it predicts electrons would emit radiation and collapse into the nucleus, not maintain stable orbits.

Question 2

What is the energy difference between the $ n = 5 $ and $ n = 3 $ states in a hydrogen atom? (Use $ E_n = -\frac{13.6}{n^2} \, \text{eV} $)

Accepted Answer

$ E_5 = -0.544 \, \text{eV} $, $ E_3 = -1.51 \, \text{eV} $. $ \Delta E = -0.544 - (-1.51) = 0.966 \, \text{eV} \approx 0.97 \, \text{eV} $.

Question 3

In Bohr’s model, what defines the stationary orbits of an electron?

Accepted Answer

Bohr’s second postulate defines stationary orbits as those where the angular momentum is an integral multiple of $ h/2\pi $.

NEET Physics: Atoms and Nuclei — Practice Set 1

Q1. Which of the following statements is incorrect about Rutherford’s nuclear model?

Q2. What is the energy difference between the \( n = 5 \) and \( n = 3 \) states in a hydrogen atom? (Use \( E_n = -\frac{13.6}{n^2} \, \text{eV} \))

Q3. In Bohr’s model, what defines the stationary orbits of an electron?

Q4. What is the wavelength of the photon emitted when an electron drops from \( n = 2 \) to \( n = 1 \) in a hydrogen atom? (Use \( h = 6.6 \times 10^{-34} \, \text{J·s} \), \( c = 3 \times 10^8 \, \text{m/s} \), 1 eV = \( 1.6 \times 10^{-19} \, \text{J} \))

Q5. What does the de Broglie hypothesis suggest about the electron in Bohr’s model?

Q6. What is the total energy of an electron in the \( n = 4 \) state of a hydrogen atom? (Use \( E_n = -\frac{13.6}{n^2} \, \text{eV} \))

Q7. In the Bohr model, how many de Broglie wavelengths fit into the circumference of the \( n = 6 \) orbit?

Q8. An electron in a hydrogen atom transitions from \( n = 3 \) to \( n = 1 \). What is the energy of the emitted photon? (Use \( E_n = -\frac{13.6}{n^2} \, \text{eV} \))

Q9. In Bohr’s model, what is the state of a hydrogen atom when its electron is in the \( n = \infty \) orbit?

Q10. What characterizes the emission line spectrum of a hydrogen atom?