BPSC PAST PAPERS MCQS
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چار آپشن میں سے کسی ایک پر کلک کرنے سے جواب سرخ ہو جائے گا۔
شیٹ میٹل ورک میں ، آلے پر کاٹنے والی قوت کو ______ کے ذریعہ کم کیا جاسکتا ہے؟
- Grinding the cutting edges sharp
- Increasing the hardness of tool
- Providing shear angle on the tool
- None of these
اس سوال کو وضاحت کے ساتھ پڑھیں
Explanation
Introducing a shear angle on the cutting tool reduces resistance and spreads the cutting force over a smaller area.
This decreases the required cutting force and improves tool efficiency.
Shear angle is the key factor in reducing cutting force.
دھاتوں کا گرم کام ______ انجام دیا جاتا ہے؟
- Adversely affects the mechanical properties of metals
- Below the recrystallisation temperature
- Above the recrystallisation temperature
- None of these
اس سوال کو وضاحت کے ساتھ پڑھیں
Explanation
Hot working is done above the recrystallisation temperature to make metals ductile and easily deformable.
It reduces internal stresses and prevents cracking during shaping.
Hot working must be above recrystallisation temperature for effective deformation.
ریفریکٹری مادے کی شناخت کریں جس میں تیزاب اور بنیادی سلیگس دونوں کے خلاف زیادہ مزاحمت ہے؟
- Fire clay bricks
- Magnesia
- Chromite bricks
- None of these
اس سوال کو وضاحت کے ساتھ پڑھیں
Explanation
Chromite bricks are highly resistant to both acidic and basic slags, making them ideal for lining furnaces in metallurgical industries.
They can withstand high temperatures and chemical attack during metal processing.
Their high thermal conductivity also helps in efficient heat transfer in industrial furnaces.
سلپ گیجز عام طور پر ______ سے بنی ہوتی ہیں؟
- Cast iron
- Wrought iron
- Alloy steel
- None of these
اس سوال کو وضاحت کے ساتھ پڑھیں
Explanation
Slip gauges (or gauge blocks) are generally made of alloy steel for high hardness, wear resistance, and dimensional stability.
They are used for precise measurement and calibration in engineering and machining.
Slip gauges can also be made of ceramic or tungsten carbide for special applications requiring corrosion resistance.
زیادہ تر مواد کے لئے تپش کا درجہ حرارت _____ کے حکم کا ہے؟
- 400 to 500 °C
- 100 – 150 °C
- 350 to 400 °C
- None of these
اس سوال کو وضاحت کے ساتھ پڑھیں
Explanation
Tempering is a heat treatment process used to reduce brittleness and improve toughness in metals, especially steel.
Most materials are tempered at temperatures in the range of 400–500 °C.
The exact tempering temperature is chosen based on the desired balance between hardness and toughness.
سخت ترین دھات کی شناخت کریں؟
- Diamond
- Iron
- Platinum
- Tungsten
اس سوال کو وضاحت کے ساتھ پڑھیں
Explanation
Tungsten is the strongest metal on Earth.
The melting point of Tungsten is ~ 3,422 °C.
The boiling point of Tungsten is ~ 5,555 °C.
کسی مواد میں سختی کی کمی کا مطلب _____ ہے؟
- Creep strength
- Brittleness
- Plasticity
- None of these
اس سوال کو وضاحت کے ساتھ پڑھیں
Explanation
Lack of toughness in a material indicates that it is brittle, meaning it breaks easily under stress without significant deformation.
Toughness is the ability to absorb energy before fracture, so low toughness increases the risk of sudden failure.
Brittle materials fail without noticeable warning, unlike ductile materials that deform before breaking.
توازن قانون کے مطابق ، دو قوتیں صرف اس صورت میں توازن ہوسکتی ہیں جب وہ _____ ہوں؟
- Collinear in action
- Equal in magnitude
- Opposite in direction
- All of the above
اس سوال کو وضاحت کے ساتھ پڑھیں
Explanation
For two forces to be in equilibrium, they must be collinear, equal in magnitude, and opposite in direction.
This ensures that the net force acting on the body is zero, keeping it at rest or in uniform motion.
This principle is a fundamental concept in statics for analyzing forces on structures and objects.
ماحولیاتی تحفظ کی ایجنسیاں کلورو فلورو کاربن ریفریجریٹ کے استعمال کے خلاف مشورہ دیتی ہیں کیوں کہ یہ _____ کے ساتھ رد عمل ظاہر کرتے ہیں؟
- Ozone layer
- Water vapour and cause acid rain
- Plastic and cause green
- None of these
اس سوال کو وضاحت کے ساتھ پڑھیں
Explanation
Chloro-fluoro carbon (CFC) refrigerants react with and destroy the ozone layer, which protects Earth from harmful UV radiation.
This depletion leads to increased UV exposure, causing health and environmental hazards.
CFCs have been largely replaced by HFCs and other eco-friendly refrigerants to reduce ozone damage.
کے مقصد کو پورا کرنے کے لئے ایک چھوٹی سی ریفریجریٹر میں ایک کیپلیری ٹیوب استعمال کی جاتی ہے؟ _____
- Evaporator
- Thermostat
- Expansion valve
- None of these
اس سوال کو وضاحت کے ساتھ پڑھیں
Explanation
A capillary tube in a small refrigerator acts as an expansion valve, controlling the flow of refrigerant into the evaporator.
It reduces the pressure of the liquid refrigerant, causing it to expand and cool in the evaporator.
The capillary tube is simple, inexpensive, and has no moving parts, making it ideal for small refrigeration systems.
