इन्जिनियरिङ प्रवेश – Mathematics, Physics, Chemistry, English
इन्जिनियरिङ प्रवेश – Mathematics, Physics, Chemistry, English
Engineering Entrance – Mathematics, Physics, Chemistry & English · ३,८४१ प्रश्न
३,८४१ प्रश्न उपलब्ध। मोड छान्नुहोस्:
इन्जिनियरिङ प्रवेश: प्रश्न र उत्तर
सही लागेको विकल्पमा थिच्नुहोस्। सही भए हरियो, गलत भए रातो देखिन्छ; ३ सेकेन्डपछि सही उत्तर र व्याख्या देखिन्छ।
सही: ० / ०
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A copper rod (K = 400 W m⁻¹ K⁻¹) of length 1 m and cross-section 1 cm² has its ends at 100 °C and 0 °C. The rate of heat flow through it is:
सही उत्तर: ख) 4 W
H = KAΔT/L = 400 × 10⁻⁴ × 100/1 = 4 W.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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The triple point of water, used as the fixed point of the Kelvin scale, is:
सही उत्तर: क) 273.16 K
The triple point of water (where ice, water and vapour coexist) is assigned exactly 273.16 K; 273.15 K corresponds to 0 °C.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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The heat needed to raise the temperature of 2 kg of water by 10 °C is (specific heat of water = 4200 J kg⁻¹ K⁻¹):
सही उत्तर: घ) 84000 J
Q = mcΔT = 2 × 4200 × 10 = 84000 J.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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In streamline flow through a narrow tube under a fixed pressure difference, if the radius of the tube is doubled, the rate of flow becomes:
सही उत्तर: ग) 16 times
By Poiseuille's equation, volume flow rate Q = πPr⁴/(8ηl) ∝ r⁴, so doubling r gives 2⁴ = 16 times.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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When the temperature is raised, the coefficient of viscosity:
सही उत्तर: ख) rises for gases but falls for liquids
Liquid viscosity falls as cohesion weakens, but gas viscosity rises because molecular momentum transfer increases with temperature.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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The excess pressure inside a spherical liquid drop of radius r and surface tension T is:
सही उत्तर: क) 2T/r
A liquid drop has only one free surface, so excess pressure = 2T/r (a soap bubble with two surfaces has 4T/r).
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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The height h to which a liquid of density ρ and surface tension T rises in a capillary of radius r (angle of contact θ) is:
सही उत्तर: घ) h = 2T cos θ/(rρg)
Balancing the upward surface tension force 2πrT cos θ with the weight πr²hρg gives h = 2T cos θ/(rρg).
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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The surface tension of a liquid generally:
सही उत्तर: ग) decreases with rise in temperature
As temperature rises, intermolecular cohesion weakens, so surface tension decreases (becoming zero at the critical temperature).
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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Bernoulli's theorem for a flowing ideal fluid is a consequence of the conservation of:
सही उत्तर: ख) energy
Bernoulli's equation P + ½ρv² + ρgh = constant expresses conservation of energy per unit volume of the fluid.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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A body weighs 10 N in air and 8 N when fully immersed in water. The relative density of the material of the body is:
सही उत्तर: क) 5
Loss of weight = upthrust = 2 N; relative density = weight in air/loss of weight = 10/2 = 5.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
यी अभ्यास प्रश्न हुन्, आधिकारिक प्रश्न होइनन्। पाठ्यक्रम, विज्ञापन र नतिजाका लागि सम्बन्धित निकायको आधिकारिक वेबसाइट हेर्नुहोस्। उत्तरमा गल्ती भेटे प्रश्नमुनिको "टिप्पणी / गल्ती रिपोर्ट" मा लेख्नुहोस्।
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