NEET Atoms and Nuclei — Set 6

Question 1

In Rutherford’s model, what is the primary force keeping electrons in orbit around the nucleus?

Accepted Answer

The electrostatic force of attraction between the positively charged nucleus and negatively charged electrons provides the centripetal force for orbiting.

Question 2

What is the ratio of the kinetic energy to the potential energy of an electron in the ground state of a hydrogen atom? (Given total energy = -13.6 eV)

Accepted Answer

$ E = K + U $, $ K = 13.6 \, \text{eV} $, $ U = -27.2 \, \text{eV} $. Ratio = $ \frac{K}{|U|} = \frac{13.6}{27.2} = 0.5 $.

Question 3

The radius of the first orbit in a hydrogen atom is $ 5.3 \times 10^{-11} \, \text{m} $. What is the radius of the second orbit?

Accepted Answer

Radius $ r_n = n^2 r_1 $, where $ r_1 = 5.3 \times 10^{-11} \, \text{m} $. For $ n = 2 $: $ r_2 = 2^2 \times 5.3 \times 10^{-11} = 4 \times 5.3 \times 10^{-11} = 2.12 \times 10^{-10} \, \text{m} $.

NEET Physics: Atoms and Nuclei — Practice Set 6

Q1. In Rutherford’s model, what is the primary force keeping electrons in orbit around the nucleus?

Q2. What is the ratio of the kinetic energy to the potential energy of an electron in the ground state of a hydrogen atom? (Given total energy = -13.6 eV)

Q3. The radius of the first orbit in a hydrogen atom is \( 5.3 \times 10^{-11} \, \text{m} \). What is the radius of the second orbit?

Q4. A hydrogen atom absorbs a photon and jumps from \( n = 1 \) to \( n = 2 \). What is the energy of the photon? (Use \( E_n = -\frac{13.6}{n^2} \, \text{eV} \))

Q5. Which of the following statements is correct about the energy levels in a hydrogen atom according to Bohr’s model?

Q6. What is the angular momentum of an electron in the \( n = 5 \) state of a hydrogen atom? (Use \( h = 6.6 \times 10^{-34} \, \text{J·s} \))

Q7. What is the wavelength of a photon emitted when an electron drops from \( n = 4 \) to \( n = 3 \) in a hydrogen atom? (Use \( h = 6.6 \times 10^{-34} \, \text{J·s} \), \( c = 3 \times 10^8 \, \text{m/s} \), 1 eV = \( 1.6 \times 10^{-19} \, \text{J} \))

Q8. How many de Broglie wavelengths fit into the circumference of the \( n = 4 \) orbit of a hydrogen atom?

Q9. A hydrogen atom in the \( n = 5 \) state emits a photon and returns to the ground state. What is the maximum energy of the photon? (Use \( E_n = -\frac{13.6}{n^2} \, \text{eV} \))

Q10. The radius of the third orbit in a hydrogen atom is how many times the radius of the first orbit if \( r_1 = 5.3 \times 10^{-11} \, \text{m} \)?