PST PAST PAPER 21-09-2021
PST Past Papers Click
here
فری تیاری کیلے Whatsappجوائن کریںClick
here
چار آپشن میں سے کسی ایک پر کلک کرنے سے جواب سرخ ہو جائے گا۔
- 50
- 40
- 30
- None of these
اس سوال کو وضاحت کے ساتھ پڑھیں
Explanation
The upper-class limit is the higher value of the class interval.
So, for (10-50), it's 50.
Last verified on 13-03-2026
انرشا کے قانون کو _____ بھی کہا جاتا ہے؟
- First Law of Motion
- Second Law of Motion
- Third Law of Motion
- None of these
اس سوال کو وضاحت کے ساتھ پڑھیں
Explanation
- Law of Inertia = Newton’s First Law of Motion.
- States: “An object at rest stays at rest, and an object in motion continues in the same direction and speed unless acted upon by an unbalanced force.”
- Explains why seat belts are important in cars.
- Applies to all objects on Earth and in space.
Last verified on 13-03-2026
سائنس لاطینی لفظ "سائنثیا" سے ماخوذ ہے جس کا مطلب ہے؟
- Knowledge
- Wisdom
- Information
- Intelligence
اس سوال کو وضاحت کے ساتھ پڑھیں
Explanation
- The word ‘Scientia’ is derived from the Latin word Scientia which means ‘knowledge’.
- Science involves observation, experimentation, and analysis.
- The scientific method includes Hypothesis → Experiment → Observation → Conclusion.
Last verified on 13-03-2026
- Planet
- Element
- Asteroid
- Star
اس سوال کو وضاحت کے ساتھ پڑھیں
Explanation
- The Sun is a star.
- There are lots of stars, but the Sun is the closest one to Earth.
- It is the center of our solar system.
- The Sun is a hot ball of glowing gases.
- The sun is composed of layers made up almost entirely of hydrogen and helium.
Last verified on 13-03-2026
جب آواز کی لہر ایک جگہ سے دوسری جگہ جاتی ہے تو کیا منتقل کیا جاتا ہے؟
- Matter
- Momentum
- Energy
- Velocity
اس سوال کو وضاحت کے ساتھ پڑھیں
Explanation
- Sound waves are mechanical waves that require a medium (air, water, or solid) to travel.
- They transport energy, not matter.
- Particles of the medium vibrate around their mean position but do not move along with the wave.
- Examples: Speaking, music, and alarms transfer energy through sound waves.
Last verified on 13-03-2026
جب روشنی پرزم سے گزرتی ہے تو _____ سپیکٹرم بنتا ہے۔
- Refraction
- Reflection
- Diffraction
- None of these
اس سوال کو وضاحت کے ساتھ پڑھیں
Explanation
- Refraction: Bending of light when it passes from one medium to another.
- A prism bends light at different angles depending on wavelength.
- This separation of colors is called dispersion, forming a spectrum.
- Visible spectrum colors: Red, Orange, Yellow, Green, Blue, Indigo, Violet (ROYGBIV).
Last verified on 13-03-2026
حرارتی توانائی کو ______ کے ذریعے منتقل کیا جا سکتا ہے؟
- Conduction
- Convection
- Radiation
- All of these
اس سوال کو وضاحت کے ساتھ پڑھیں
Explanation
Thermal energy can be transferred through all three methods:
- Conduction: Direct transfer between particles in physical contact.
- Convection: Transfer through the movement of fluids.
- Radiation: Transfer through electromagnetic waves (e.g., light, radio waves).
Last verified on 13-03-2026
برف کے ٹوپوں کے نیچے کا علاقہ جس کا موسم بہت سرد ہو، اسے کیا کہا جاتا ہے؟
- Forest
- Grassland
- Tundra
- Desert
اس سوال کو وضاحت کے ساتھ پڑھیں
Explanation
- Tundra is a cold, treeless region found near the Arctic and Antarctic.
- Soil is often frozen (permafrost) throughout the year.
- Vegetation includes mosses, lichens, and low shrubs.
- Animals adapted: polar bears, arctic foxes, reindeer.
Last verified on 13-03-2026
مندرجہ ذیل میں سے کس ردعمل میں دو مرکبات اپنے ریڈیکلز/آئنز کا تبادلہ کرتے ہیں؟
- Double Displacement
- Decomposition
- Combination
- None of these
اس سوال کو وضاحت کے ساتھ پڑھیں
Explanation
- Double Displacement Reaction: Two compounds exchange ions or radicals to form new compounds.
- General form: AB + CD → AD + CB.
- Example: Na₂SO₄ + BaCl₂ → BaSO₄ + 2NaCl
Additional information:
- Decomposition: Single compound breaks into two or more simpler substances.
- Combination (Synthesis): Two or more substances combine to form one compound.
Last verified on 13-03-2026
کسی مادّہ کا سب سے چھوٹا ذرہ جو اس مادّہ کی تمام خصوصیات رکھتا ہو کیا کہلاتا ہے؟
- An atom
- A molecule
- A compound
- An element
اس سوال کو وضاحت کے ساتھ پڑھیں
Explanation
- A molecule is the smallest particle of a substance that retains its chemical properties.
- It is made of two or more atoms chemically bonded together.
- Examples of molecules: H₂O, O₂, CO₂, NH₃, CH₄.
Additional information:
- An atom is the smallest unit of an element.
- A compound is a substance formed when different elements combine chemically.
Last verified on 13-03-2026