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حرارت، حرکیات حرارت اور سیال
6 سوالات: ایم ڈی کیٹ طبیعیات، جوابات اور وضاحت کے ساتھ۔
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A gas absorbs 500 J of heat and does 200 J of work. What is the change in its internal energy?
- 1 200 J
- 2 300 J
- 3 500 J
- 4 700 J
جواب دیکھیں
درست جواب: 300 J
By the first law, change in internal energy = Q - W = 500 - 200 = 300 J.
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What pressure does a force of 100 N exert on an area of 0.5 m2?
- 1 50 Pa
- 2 200 Pa
- 3 500 Pa
- 4 20 Pa
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How much heat is needed to raise the temperature of 2 kg of water by 5 degrees C? (Specific heat of water = 4200 J/kg per degree C)
- 1 4200 J
- 2 21000 J
- 3 42000 J
- 4 84000 J
جواب دیکھیں
درست جواب: 42000 J
Q = mc x temperature change = 2 x 4200 x 5 = 42000 J.
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Absolute zero is:
- 1 0 degrees C
- 2 -100 degrees C
- 3 -273.15 degrees C
- 4 -373 degrees C
جواب دیکھیں
درست جواب: -273.15 degrees C
Absolute zero, 0 K, is equal to -273.15 degrees C. It is the lowest possible temperature.
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According to Bernoulli's principle, in a horizontal flow of a fluid, where the speed is higher:
- 1 The pressure is higher
- 2 The pressure is lower
- 3 The pressure is unchanged
- 4 The density increases
جواب دیکھیں
درست جواب: The pressure is lower
A faster-moving fluid has lower pressure. This is how an aeroplane wing helps produce lift.
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Archimedes' principle says that the upthrust on a body in a fluid equals:
- 1 The weight of the body
- 2 The weight of the fluid displaced
- 3 The volume of the body only
- 4 The density of the fluid
جواب دیکھیں
درست جواب: The weight of the fluid displaced
The buoyant force is equal to the weight of the fluid pushed aside by the body.