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Showing posts with the label JEE Mains 2025

A monatomic gas having γ = 5/3 is stored in a thermally insulated container and the gas is suddenly compressed to (1/8)ᵗʰ of its initial volume. The ratio of final pressure and initial pressure is:

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  🔥 Adiabatic Compression of Monatomic Gas | Thermodynamics | JEE Physics | Doubtify 📌 Question: A monatomic gas having γ = 5 3 \gamma = \frac{5}{3} ​ is stored in a thermally insulated container , and the gas is suddenly compressed to 1 8 th \frac{1}{8}^\text{th} of its initial volume. What is the ratio of final pressure to initial pressure ? 🖼️ Question Image:

Electric charge is transferred to an irregular metallic disk as shown in the figure. If the surface charge densities at four points are σ₁, σ₂, σ₃, and σ₄, then which of the following options is correct?

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  ⚡ Surface Charge Distribution on Irregular Conductor – Electrostatics | JEE Physics | Doubtify JEE 📌 Question: Electric charge is transferred to an irregular metallic disk as shown in the figure. If the surface charge densities at four points are σ₁, σ₂, σ₃, and σ₄ , then which of the following options is correct ?

Surface Charge Density After Contact – Ratio σ₁/σ₂ | JEE Electrostatics | Doubtify JEE

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  ⚡ Surface Charge Density After Contact – Electrostatics | JEE Physics | Doubtify JEE 📌 Question: Two metal spheres of radius R and 3R have the same surface charge density σ . They are brought in contact and then separated . After separation, let the surface charge densities be σ₁ (for smaller sphere) and σ₂ (for larger sphere). What is the ratio σ₁ / σ₂ ? 🖼️ Question Image:

Momentum vs Height Graph – Vertical Motion of Ball | JEE Physics Graphs | Doubtify JEE

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  🏐 Momentum vs Height Graph – Vertical Motion | JEE Physics | Doubtify JEE 📌 Question: A ball is thrown vertically upwards (take +z-axis as upwards) from the ground. 👉 Which of the following momentum-height (p–h) graphs correctly represents the motion? This is a concept-based question that checks your understanding of vector momentum and energy conservation . 🖼️ Question Image:

Uniform Acceleration Graphs – Motion from Rest | JEE Physics Graphs | Doubtify JEE

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  🚀 Uniform Acceleration Motion Graphs | Kinematics | Doubtify JEE 📌 Question: A particle starts from origin O from rest and moves with a uniform acceleration along the positive x-axis . 👉 Identify all the graphs that correctly represent the motion qualitatively: a = acceleration v = velocity x = displacement t = time This is a conceptual question testing your understanding of motion graphs! 🖼️ Question Image:

Relative Motion of Two Ships | Minimum Distance Concept | JEE Physics Problem with Solution

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  🧭 Relative Motion of Ships – Minimum Distance Concept | JEE Physics | Doubtify JEE 📌 Question: Ship A is sailing towards north-east with velocity v = 30 î + 50 ĵ km/h , where î points east and ĵ points north . Ship B is at a distance of 80 km east and 150 km north of Ship A and is sailing west at 10 km/h . 🔍 Find the time at which Ship A is at minimum distance from Ship B. 🖼️ Question Image:

⚗️ Empirical Formula from Combustion Data – Chemistry JEE | Doubtify JEE

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🧪 Question: The ratio of mass percent of C and H of an organic compound (CxHyOz) is 6:1. If one molecule of the above compound contains half as much oxygen as required to burn one molecule of compound CxHy completely to CO₂ and H₂O, then what is the empirical formula of the compound? 📌 Why This Question is Important: This question combines two highly testable concepts in JEE Chemistry – combustion analysis and empirical formula derivation . You’re not only working with mass percent ratio , but also applying oxygen balancing logic in a combustion reaction. Such questions are frequently seen in organic chemistry chapters , particularly under Basic Principles of Organic Chemistry and Stoichiometry . Mastering this helps you crack more complex analysis-based questions in JEE Mains and even Advanced . 💡 Concept Used: To find the empirical formula , we first convert the mass percent ratio of C and H into moles , assuming 100 g of substance. Then we apply a stoichiometric appr...