EVERYDAY SCIENCE
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چار آپشن میں سے کسی ایک پر کلک کرنے سے جواب سرخ ہو جائے گا۔
- The component with higher density
- The component with higher boiling point
- The component with lower boiling point
- None of these
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Explanation
- In distillation, the liquid with the lower boiling point evaporates first because it requires less heat to become vapor.
- The vapor is then cooled and collected as the more volatile component.
- Components with higher boiling points remain in the liquid phase longer.
Last verified on 26-06-2026
- Dry bulb temperature increases
- Moisture content remain constant
- Water vapor condenses continuously
- None of these
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Explanation
- At 18°C, air reaches its dew point, so condensation starts.
- If cooling continues below 18°C, more water vapor changes into liquid water.
- Therefore, water vapor condenses continuously and moisture content decreases.
Last verified on 26-06-2026
- No vapor phase will form
- Separation is easy with few trays
- Separation is difficult and requires many stages
- None of these
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Explanation
Relative volatility α = 1.05 means the two components have almost the same volatility.
Rule of thumb:
- α >> 1 → easy separation, few trays
- α ≈ 1 → difficult separation, needs many equilibrium stages + high reflux
- α = 1 → no separation possible by distillation
Here α = 1.05 is very close to 1, so simple distillation won’t work well. You’d need many stages/plates and high energy.
Last verified on 25-06-2026
- 300 kJ/kg
- 20 kJ/kg
- 40 kJ/kg
- None of these
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Explanation
For a nozzle: steady flow energy equation, adiabatic, no work, PE negligible.
h₁ + KE₁ = h₂ + KE₂
Given:
h₁ = 300 kJ/kg, h₂ = 260 kJ/kg, KE₁ ≈ 0 because inlet velocity is negligible
KE₂ = h₁ - h₂
KE₂ = 300 - 260 = 40 kJ/kg
Last verified on 26-06-2026
- Pressure decreases but remains above 300 kPa
- Pressure remains constant
- Pressure decreases below 300 kPa
- None of these
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Explanation
Polytropic: P V^n = C, here n = 2.0
So P₁ V₁² = P₂ V₂²
Given: P₁ = 1000 kPa, V₁ = 1 m³, V₂ = 2 m³
P₂ = P₁ × V₁² / V₂²
P₂ = 1000 × 1² / 2²
P₂ = 1000 / 4 = 250 kPa
Volume doubles → pressure drops to 1/4.
250 kPa is below 300 kPa, so pressure decreases below 300 kPa.
Last verified on 26-06-2026
- 0.80 g/L
- 1.5 g/L
- 10 g/L
- None of these
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Explanation
For ideal gas: Density d = PM / RT
Given:
P = 8.21 atm, M = 28 g/mol, T = 280 K, R = 0.0821 L·atm/mol·K
d = (8.21 × 28) / (0.0821 × 280)
d = 229.88 / 22.988
d ≈ 10 g/L
Last verified on 26-06-2026
- 248 Κ
- 273 Κ
- 298 K
- None of these
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Explanation
Formula: K = °C + 273.15
So 25°C = 25 + 273.15 = 298.15 K.
Last verified on 26-06-2026
- 2.0 atm
- 3.0 atm
- 4.5 atm
- None of these
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Explanation
Volume is constant → use Gay-Lussac's Law: P₁/T₁ = P₂/T₂
Given:
P₁ = 1.5 atm, T₁ = 300 K, T₂ = 600 K
P₂ = P₁ × T₂ / T₁
P₂ = 1.5 × 600 / 300
P₂ = 900 / 300 = 3.0 atm
Temp doubled from 300 K to 600 K, so pressure also doubles from 1.5 atm to 3.0 atm.
Last verified on 26-06-2026
- 6.0 L
- 3.5 L
- 4.5 L
- None of these
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Explanation
Pressure is constant → use Charles's Law: V₁/T₁ = V₂/T₂
Given:
V₁ = 3.0 L, T₁ = 300 K, T₂ = 450 K
V₂ = V₁ × T₂ / T₁
V₂ = 3.0 × 450 / 300
V₂ = 1350 / 300 = 4.5 L
So when temp goes from 300 K to 450 K, volume increases from 3.0 L to 4.5 L.
Last verified on 26-06-2026
پودوں میں کاربن ڈائی آکسائیڈ اور آکسیجن کس ذریعے حرکت کرتے ہیں؟
- Stomata
- Xylem
- Phloem
- None of these
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Explanation
- Carbon dioxide (CO₂) and oxygen (O₂) move in plants through stomata.
- Stomata are tiny pores present on leaves.
- These gases move by diffusion, not active transport.
- They are essential for photosynthesis and respiration.
Last verified on 25-06-2026