JEST 5 YEARS PAST PAPERS PDF
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چار آپشن میں سے کسی ایک پر کلک کرنے سے جواب سرخ ہو جائے گا۔
آواز کی رفتار درج ذیل میں سے کس میں زیادہ سے زیادہ ہوتی ہے؟
- Air
- Glass
- Water
- Steel
اس سوال کو وضاحت کے ساتھ پڑھیں
Explanation
- Solids → fastest sound speed
- Liquids → medium speed
- Gases → slowest speed
Steel is more elastic and dense.
- Steel ≈ 5000 m/s
- Air ≈ 332 m/s
- Water ≈ 1500 m/s
Last verified on 11-04-2026
بوائل کا قانون کہتا ہے کہ مستقل درجہ حرارت پر کیا ہوتا ہے؟
- PV = constant
- P ∝ V
- P ∝ T
- None of these
اس سوال کو وضاحت کے ساتھ پڑھیں
Explanation
- Boyle’s law explains the relationship between pressure and volume.
- At constant temperature, pressure is inversely proportional to volume.
- When pressure increases, volume decreases and vice versa.
- Boyle’s law: P ∝ 1/V
- Equation: PV = constant
Last verified on 11-04-2026
درج ذیل میں سے کون سا مقدار رفتار کی تبدیلی کی شرح کو ظاہر کرتا ہے؟
- Displacement
- Acceleration
- Momentum
- None of these
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Explanation
- The rate of change of velocity is called acceleration.
- It shows how quickly velocity changes with time.
- Velocity may change in speed or direction.
- Displacement is change in position.
- Momentum depends on mass and velocity.
Last verified on 11-04-2026
درج ذیل میں سے کون سا آپشن مادوں میں بندش کی درست قسم کو ظاہر کرتا ہے؟
- Potassium chloride has ionic bonding ; Graphite has ionic bonding
- Methane has ionic bonding ; Graphite has covalent bonding
- Graphite has ionic bonding ; Chloride has covalent bonding
- Potassium chloride has ionic bonding ; Methane has covalent bonding
اس سوال کو وضاحت کے ساتھ پڑھیں
Explanation
- Ionic bonding occurs between metals and non-metals.
- Potassium chloride (KCl) is formed from potassium (metal) and chlorine (non-metal), so it is ionic.
- Covalent bonding occurs between non-metal atoms.
- Methane (CH₄) is formed by sharing electrons, so it is covalent.
Last verified on 11-04-2026
درج ذیل میں سے کون سا بیان کمزور تیزاب کی خاصیت کو ظاہر نہیں کرتا؟
- It has a pH of between 8 and 9
- It forms a salt with sodium hydroxide
- It is only partly dissociated into ions
- It reacts with sodium carbonate to give off carbon dioxide
اس سوال کو وضاحت کے ساتھ پڑھیں
Explanation
- Weak acids partially dissociate in water.
- They have a pH less than 7, usually around 4–6.
- A pH of 8–9 indicates a weak base, not an acid.
- Weak acids still react with bases and carbonates.
- Therefore, pH 8–9 is not a property of weak acids.
Last verified on 11-04-2026
درج ذیل میں سے کون سا بیان کیمیائی توازن کو ظاہر نہیں کرتا؟
- Kc increases as the reaction progresses
- Forward and backward reactions occur at an equal rate
- The system must be closed
- Concentrations of reactants and products are constant
اس سوال کو وضاحت کے ساتھ پڑھیں
Explanation
- Chemical equilibrium is a state where forward and backward reactions occur at the same rate.
- At equilibrium, concentrations of reactants and products remain constant.
- It occurs in a closed system.
- The equilibrium constant (Kc) remains constant, not increasing.
- Therefore, Kc increasing is not a feature of equilibrium.
Last verified on 11-04-2026
نمکیات تیزاب اور اساس (بیس) کے ردعمل سے بنتے ہیں۔ تیاری کے ٹائٹریشن طریقہ کے لیے کون سا تیزاب اور اساس کا امتزاج موزوں ہے؟
- An insoluble acid with a soluble base
- A soluble acid with an insoluble base
- A soluble acid with a soluble base
- None of these
اس سوال کو وضاحت کے ساتھ پڑھیں
Explanation
- Titration is a method used to prepare soluble salts.
- It works when both acid and base are in solution form.
- A soluble acid reacts completely with a soluble base.
- This allows accurate measurement and neutralization.
- Therefore, both must be soluble for titration method.
Last verified on 11-04-2026
درج ذیل میں سے کون سا عمل تصادم کی تعداد یا نوعیت کو متاثر کر کے ری ایکشن کی رفتار میں اضافہ نہیں کرتا؟
- Increasing the temperature
- Adding a catalyst
- Increasing the pressure
- Increasing the surface area
اس سوال کو وضاحت کے ساتھ پڑھیں
Explanation
- Reaction rate depends on collision frequency and energy.
- Temperature, pressure, and surface area increase collision number.
- A catalyst increases reaction rate but does not change collisions directly.
- It works by lowering activation energy, not by changing collisions.
Last verified on 11-04-2026
درج ذیل میں سے کون سا عمل اینڈوتھرمک (حرارت جذب کرنے والا) ہے؟
- 2H₂(g) + O₂(g) → 2H₂O(l)
- H(g) + Cl(g) → HCl(g)
- H₂O(g) → 2H(g) + O₂(g)
- H₂O(l) → H₂O(s)
اس سوال کو وضاحت کے ساتھ پڑھیں
Explanation
- H₂O(g) → 2H(g) + O₂(g)
- Endothermic reactions absorb heat from the surroundings.
- Breaking bonds requires energy input.
- Water vapour (H₂O) is broken into atoms, which needs energy.
- Therefore, this process is endothermic.
Last verified on 11-04-2026
ایک آمیزہ تیزاب اور الکلی دونوں کے ساتھ ردعمل کرنے پر گیس پیدا کرتا ہے۔ اس میں کون سے آئن موجود ہیں؟
- Hydrogen ions and oxide ions
- Ammonium ions and carbonate ions
- Ammonium ions and oxide ions
- None of these
اس سوال کو وضاحت کے ساتھ پڑھیں
Explanation
- Some ions release gas in specific chemical reactions.
- Ammonium ions release ammonia gas when reacting with alkali.
- Carbonate ions release carbon dioxide gas when reacting with acid.
- Since gas is produced with both acid and alkali, both ions must be present.
Last verified on 11-04-2026
