PST 5 YEARS PAST PAPERS PDF
چار آپشن میں سے کسی ایک پر کلک کرنے سے جواب سرخ ہو جائے گا۔
مندرجہ ذیل میں سے کون سا گرمی کا اچھا موصل ہے؟
- Wood
- Plastic
- Paper
- Copper
اس سوال کو وضاحت کے ساتھ پڑھیں
Explanation
- Copper is an excellent conductor of heat.
- It having a high thermal conductivity (386 W/mK).
- This means it can efficiently transfer heat energy with minimal resistance.
- Metals (e.g., iron, copper, silver, mercury, aluminum) are good conductors of heat.
Last verified on 19-03-2026
مائعات اور گیسوں میں حرارت کی منتقلی کس طریقے سے ہوتی ہے؟
- Convection
- Radiation
- Conduction
- None of these
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Explanation
- In liquids and gases, heat is mainly transferred by convection.
- Convection involves the movement of particles carrying heat from one place to another.
- Essential for weather patterns, ocean currents, and heating systems.
Last verified on 19-03-2026
شور کی آلودگی / شدت کس میں ماپی جاتی ہے؟
- Decibels (dB)
- Hertz (Hz)
- Watts (W)
- Meters (m)
اس سوال کو وضاحت کے ساتھ پڑھیں
Explanation
- Noise intensity is measured in decibels (dB).
- It indicates the loudness of sound.
- It helps assess noise pollution in cities, industries, and traffic areas.
- Noise pollution affects hearing, stress levels, and sleep.
- Reducing exposure above 85 dB is important for health protection.
Last verified on 19-03-2026
بجلی سے روشنی کی چمک تقریبا ____ پر سفر کرتی ہے؟
- 2 x 10^5 m/s
- 1 x 10^4 m/s
- 5 x 10^6 m/s
- 3 x 10^8 m/s
اس سوال کو وضاحت کے ساتھ پڑھیں
Explanation
- The flash of light from lightning is a form of electromagnetic radiation, and as such, it travels at the speed of light.
- It is denoted by the letter c.
It is equal to:
- 3 x 10^8 meters per second (m/s) in scientific notation.
- 300,000 kilometers per second (km/s) in metric units.
- 186,282 miles per second (mi/s) in imperial units
Last verified on 19-03-2026
ٹریٹیم آئسوٹوپ کے نیوکلئس میں کتنے پروٹون اور نیوٹران موجود ہیں؟
- 2 and 1
- 1 and 2
- 3 and 2
- 4 and 1
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Explanation
- Tritium, also known as superheavy hydrogen.
- It has 1 proton and 2 neutrons in its atomic nucleus.
Additional information:
- Protium (¹H) → 1 proton, 0 neutrons
- Deuterium (²H) → 1 proton, 1 neutron
Last verified on 19-03-2026
الفابیٹ کی کے مدار میں الیکٹران کی زیادہ سے زیادہ تعداد کتنی ہے؟
- 2
- 4
- 6
- 8
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Explanation
The K orbit, also known as the first electron shell.
- It can hold a maximum of 2 electrons.
The L orbit, also known as the second electron shell.
- It can hold a maximum of 8 electrons.
The M orbit, also known as the third electron shell.
- It can hold a maximum of 18 electrons.
Last verified on 19-03-2026
ایٹم کے نیوکلئس میں پروٹان اور نیوٹران کا مجموعہ ____ کے نام سے جانا جاتا ہے؟
- Atomic Mass
- Mass Number
- Atomic Number
- Valance Number
اس سوال کو وضاحت کے ساتھ پڑھیں
Explanation
- The mass number (A) is the sum of protons and neutrons present in the nucleus of an atom.
- It is a measure of the total number of nucleons (protons and neutrons) in the nucleus.
- It helps determine the atomic mass and distinguishes isotopes of an element.
Last verified on 19-03-2026
مندرجہ ذیل میں سے کون سی گولیاں پانی صاف کرنے کے لیے استعمال ہوتی ہیں؟
- Aspirin
- Antibiotic
- Vitamin C
- Halazone
اس سوال کو وضاحت کے ساتھ پڑھیں
Explanation
- Halazone tablets are used to purify drinking water by killing bacteria and pathogens.
- Commonly used in emergencies, military, or travel situations where safe water is unavailable.
- Halazone tablets can purify 1 liter of water in about 5–10 minutes.
Last verified on 19-03-2026
زمین پر پانی کا کتنا فیصد کھارا پانی ہے؟
- 90%
- 95%
- 98.5%
- 97.5%
اس سوال کو وضاحت کے ساتھ پڑھیں
Explanation
- About 97.5% of the water on Earth is saltwater, found in oceans, seas, and salt lakes.
- The remaining 2.5% is freshwater, found in rivers, lakes, wetlands, and underground aquifers.
Last verified on 19-03-2026
مندرجہ ذیل میں سے کون سا جانور ثانوی صارف ہے؟
- Dog
- Cat
- Cow
- Both A and B
اس سوال کو وضاحت کے ساتھ پڑھیں
Explanation
- Cat and Dog is/are a secondary consumer.
- Because they eats primary consumers (herbivores).
- Like mice, birds, and rabbits.
Last verified on 19-03-2026