Cbq Engine

---
target: 495+/500
author: Senior Sibling
name: cbq-engine
description: >-
  12th Grade Competency-Based Question (CBQ) Engine. 
  Strategies for Case Studies (Section E), Assertion-Reason, and Data-Interpretation (Physics/Bio/CS).
---

# CBQ Engine — Mastering 12th Grade Competency

CBSE 2026-27 papers are **50% Competency-Based**. This means you cannot rely on rote memorization. You must be able to **Apply** 12th Grade concepts to real-world scenarios, experimental data, and case studies.

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## 1. Case Study Strategy (Section E - 4 Marks each)

### 🔭 Physics Case Study
- **The Pattern:** Usually a passage on a modern application (e.g., MRI using Superconductivity, or Fiber Optics for high-speed internet).
- **The Questions:** 1 direct, 1 conceptual, and 2 application-based.
- **Example Scenario:** A passage on **Total Internal Reflection** in optical fibers.
    - *Q1:* State the conditions for TIR. (Direct).
    - *Q2:* Why is the cladding's refractive index lower than the core? (Conceptual).
    - *Q3:* Calculate the critical angle if $n_{core} = 1.5$. (Numerical).

### 🧪 Chemistry Case Study
- **The Pattern:** Passage on an industrial process (e.g., Haber process, Fuel cells) or a complex organic chain.
- **Example Scenario:** A passage on **Electrochemistry** in rechargeable batteries.
    - *Q1:* Define the term 'Primary Cell'.
    - *Q2:* Write the overall cell reaction during discharging.
    - *Q3:* Why does the cell potential remain constant in Mercury cells?

### 🧬 Biology Case Study
- **The Pattern:** Experimental data or a medical case (e.g., Pedigree analysis or IVF results).
- **Example Scenario:** Data on **Genetics** showing a cross between two plants.
    - *Q1:* Identify the genotype of the F1 generation.
    - *Q2:* Explain the law of Independent Assortment.
    - *Q3:* Predict the ratio of the F2 generation using a Punnett Square.

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## 2. Assertion-Reasoning (AR) Logic (1 Mark each)

The AR questions are the "Mark-Siphoners". You must follow the **Senior Sibling 2-Step Check**:

1.  **Independent Verification:** Read Assertion (A) and Reason (R) separately. Are they both true?
    - If one is False, the answer is fixed (C or D).
2.  **The "BECAUSE" Link:** If both are True, read them as one sentence: "[A] **because** [R]".
    - Does it make logical sense?
    - *Example:* (A) Phenol is more acidic than Alcohols. (R) Phenoxide ion is resonance stabilized.
    - *Check:* Phenol is more acidic **because** phenoxide ion is resonance stabilized. (True → Option A).

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## 3. Data-Interpretation (Computer Science & Physics)

- **Physics:** Interpreting V-I graphs for non-ohmic conductors or Photoelectric current vs Intensity graphs.
- **Computer Science:** Interpreting the results of a SQL `GROUP BY` query on a table of 50+ rows.
- **Biology:** Interpreting a population growth curve (S-shaped vs J-shaped).

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## 🚀 The `/cbq-practice` Command
Use this command to generate a targeted session:
- **Input:** `/cbq-practice physics "Optics" 2`
- **Output:** 2 Case Studies specifically designed to mimic the 2027 Board level, including data interpretation and multi-part questions.

**Senior Sibling Tip:** In a Case Study, the answer to part (i) often provides a clue or a value needed for part (ii). Solve them **sequentially**.