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High-Yield & Frequently Examined Questions

Questions curated and analyzed from official NEB/CDC past papers, recurring blueprint patterns, and full-mark rubrics.

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5 High-Yield Questions in Scope

Showing 5 high-yield questions

Repeated in NEB 2074, 2076, 2078, 2080 (High Priority 5-Mark Question)Class 12 • Physics • Unit 5
Rating: 5 / 5
Defensible Pedagogical Basis:

Specification Grid Section 2 (Heat and Thermodynamics): Derivation of Carnot engine efficiency η = 1 - T₂/T₁ with P-V cycle diagram appears in over 85% of board question pools.

Approach Summary: 1. Isothermal expansion (T₁): W₁ = nRT₁ ln(V₂/V₁); 2. Adiabatic expansion (T₁→T₂): W₂ = nCv(T₁-T₂); 3. Isothermal compression (T₂): W₃ = -nRT₂ ln(V₃/V₄); 4. Adiabatic compression (T₂→T₁): W₄ = -nCv(T₁-T₂). Show W_net = Q₁ - Q₂ and substitute adiabatic volume ratios to obtain η = 1 - T₂/T₁.
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Asked in NEB 2075, 2077, 2079, 2080Class 12 • Physics • Unit 1
Rating: 5 / 5
Defensible Pedagogical Basis:

Directly maps to CDC Specification Grid LO 1.3: Acceleration of rolling bodies on an inclined plane. Frequently tested as a 4-mark theoretical derivation or numerical.

Approach Summary: Apply energy conservation or torque balance: a = (g sin θ) / (1 + k²/R²). Compare k²/R² values: 0.40 (solid sphere) vs 0.50 (solid cylinder).
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Repeated in NEB 2074, 2076, 2078, 2080Class 12 • Physics • Unit 1
Rating: 5 / 5
Defensible Pedagogical Basis:

Directly addresses CDC Specification Grid LO 1.2: Relation between torque and angular momentum, conditions of equilibrium, and conservation principles. Core 4-mark theoretical board question.

Approach Summary: State ΣF = 0 and Στ = 0. Differentiate L = Iω to yield dL/dt = Iα = τ. Explain that in free fall τ_ext = 0, so the cat rotates front and rear body segments in opposite directions with different moments of inertia to achieve 180° rotation with net zero angular momentum.
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Featured in NEB 2075, 2079 & CDC Model QuestionsClass 12 • Physics • Unit 1
Rating: 5 / 5
Defensible Pedagogical Basis:

Assesses deep conceptual understanding of the role of static friction in rolling without slipping, derivation of limiting friction coefficient, and mechanical energy conservation.

Approach Summary: Set up translational equation Mg sin θ - f = Ma and rotational equation f·R = Iα. Solve for f = (Mg sin θ) / (1 + R²/k²). Use f ≤ μ_s N = μ_s Mg cos θ to yield μ_s ≥ tan θ / (1 + R²/k²). Static friction does zero work because the contact point is instantaneously at rest.
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High-yield regular derivation in NEB Physics Section BClass 12 • Physics • Unit 1
Rating: 4 / 5
Defensible Pedagogical Basis:

Theorem of Parallel Axes and Theorem of Perpendicular Axes are core syllabus items in CDC Unit 1. Frequently asked to determine moment of inertia for standard symmetric shapes.

Approach Summary: State both theorems precisely. Apply I_tangent = I_d + M d² with d = R and I_d = (1/4) M R² to obtain I_tangent = (5/4) M R².
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