#Bohr model

PHYSICS

In the Bohr model, how many de Broglie wavelengths fit into the circumference of the n = 5 orbit?

Given: In the Bohr model, how many de Broglie wavelengths fit into the circumference of the n = 5 orbit? Formula: 2π r_n = nlambda. Substitution & Calculation: For n = 5, number of wavelengths = 5. Final Result: The computed value matches expected outcome and confirms correct choice as per latest NCERT 2026-27.

Ref: NCERT Physics Textbook - Latest Edition for Academic Session 2026-27 (Rationalized Textbook for Class XI and XII, continuing as per NCERT advisory for 2026-27),Topic: Fundamental laws, definitions and applications as per latest NCERT. The section explains governing laws, formulas like μ₀ = 4π.

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PHYSICS

In the Bohr model, how many de Broglie wavelengths fit into the circumference of the n = 6 orbit?

Given: In the Bohr model, how many de Broglie wavelengths fit into the circumference of the n = 6 orbit? Formula: 2π r_n = nlambda. Substitution & Calculation: For n = 6, number of wavelengths = 6. Final Result: The computed value matches expected outcome and confirms correct choice as per latest NCERT 2026-27.

Ref: NCERT Physics Textbook - Latest Edition for Academic Session 2026-27 (Rationalized Textbook for Class XI and XII, continuing as per NCERT advisory for 2026-27),Topic: Fundamental laws, definitions and applications as per latest NCERT. The section explains governing laws, formulas like μ₀ = 4π.

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PHYSICS

The speed of an electron in the first orbit of a hydrogen atom is 2.2 × 10⁶ m/s . What is its speed in the second orb

Given: The speed of an electron in the first orbit of a hydrogen atom is 2.2 × 10⁶ m/s . What is its speed in the second orbit? These values define the system as per NCERT data. Formula: v_n = v_1/n, v_1 = 2.2 × 10⁶ m/s. This is the standard NCERT relation for this phenomenon. Substitution & Calculation: For n = 2 : v_2 = 2.2 × 10⁶/2 = 1.1 × 10⁶ m/s . Result: The computed value matches the expected outcome and confirms the correct choice. Units and powers like J kg⁻¹ K⁻¹, m/s², 10⁻⁵ are properly used as per NCERT.

Ref: NCERT Physics Textbook for Class XI and XII, Chapter: Dual Nature, Atoms, Nuclei and Electronic Devices, Topic: Atomic structure, nuclear binding and semiconductor physics.

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Shapes of Orbitals - s p d f and Nodes and Radial Probability

The angular momentum of an electron in the fourth orbit of a hydrogen atom is 4.22 × 10⁻³⁴ J s. What is its energy in eV

n=4. E₄ = -13.6/16 = -0.85 eV.

Ref: NCERT Class 11 Chemistry > Chapter 2: Structure of Atom > Topic: Shapes of Orbitals - s p d f and Nodes and Radial Probability

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Shapes of Orbitals - s p d f and Nodes and Radial Probability

The ratio of the radii of the fourth orbit of H to the third orbit of Be³⁺ is: (r₁ for H = 5.29 × 10⁻¹¹ m)

r₄(H)/r₃(Be³⁺) ≈ 7.11.

Ref: NCERT Class 11 Chemistry > Chapter 2: Structure of Atom > Topic: Shapes of Orbitals - s p d f and Nodes and Radial Probability

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Shapes of Orbitals - s p d f and Nodes and Radial Probability

The radius of the third orbit of a hydrogen atom is 4.761 × 10⁻¹⁰ m. What is the angular momentum of an electron in the

L = nh/2π, for n=5, L = 5 × 6.626×10⁻³⁴ / (2×3.14) = 5.275×10⁻³⁴ J s.

Ref: NCERT Class 11 Chemistry > Chapter 2: Structure of Atom > Topic: Shapes of Orbitals - s p d f and Nodes and Radial Probability

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Quantum Numbers - Principal Azimuthal Magnetic Spin

The number of spectral lines produced when an electron falls from n = 8 to n = 4 in a hydrogen atom is:

Number of lines = (8-4)(8-4+1)/2 = 10; actual distinct transitions = 7.

Ref: NCERT Class 11 Chemistry > Chapter 2: Structure of Atom > Topic: Quantum Numbers - Principal Azimuthal Magnetic Spin

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Quantum Numbers - Principal Azimuthal Magnetic Spin

The ratio of the kinetic energies of an electron in the first orbit of Li²⁺ to the second orbit of H is: (v₁ for H = 2.1

KE₁(Li²⁺)/KE₂(H) = 9.

Ref: NCERT Class 11 Chemistry > Chapter 2: Structure of Atom > Topic: Quantum Numbers - Principal Azimuthal Magnetic Spin

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Quantum Numbers - Principal Azimuthal Magnetic Spin

The angular momentum of an electron in the fourth orbit of He⁺ is 4.22 × 10⁻³⁴ J s. What is the frequency of the photon

n=4. ΔE ≈ 1.635×10⁻¹⁸ J. ν ≈ 2.467×10¹⁵ Hz.

Ref: NCERT Class 11 Chemistry > Chapter 2: Structure of Atom > Topic: Quantum Numbers - Principal Azimuthal Magnetic Spin

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Quantum Numbers - Principal Azimuthal Magnetic Spin

What is the radius ratio of the third orbit to the first orbit in a hydrogen atom?

rₙ = r₁ × n². r₃/r₁ = 9.

Ref: NCERT Class 11 Chemistry > Chapter 2: Structure of Atom > Topic: Quantum Numbers - Principal Azimuthal Magnetic Spin

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Electronic Configuration - Aufbau Pauli Hund and Stability

The energy of an electron in the second orbit of a hydrogen atom is -5.45 × 10⁻¹⁹ J. What is its energy in the fourth or

E₄ = -2.18×10⁻¹⁸/16 = -1.3625×10⁻¹⁹ J.

Ref: NCERT Class 11 Chemistry > Chapter 2: Structure of Atom > Topic: Electronic Configuration - Aufbau Pauli Hund and Stability

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Electronic Configuration - Aufbau Pauli Hund and Stability

The radius of the second orbit of a hydrogen atom is 2.116 × 10⁻¹⁰ m. What is the velocity of the electron in the fourth

v₄ = v₁/4 = 5.475×10⁵ m s⁻¹.

Ref: NCERT Class 11 Chemistry > Chapter 2: Structure of Atom > Topic: Electronic Configuration - Aufbau Pauli Hund and Stability

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