भौतिक विज्ञान – Physics MCQ
भौतिक विज्ञान – कृषि/वन प्रवेश
Physics · Agriculture, Veterinary & Forestry Entrance · ४२५ प्रश्न
४२५ प्रश्न उपलब्ध। मोड छान्नुहोस्:
भौतिक विज्ञान: 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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The kinetic energy of a ball rolling on smooth ground is:
सही उत्तर: क) Zero
In the absence of friction or other dissipative forces, the kinetic energy of an object in motion remains constant. Therefore, the kinetic energy of a ball rolling on smooth ground is zero.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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A swimmer is floating in a pool. The buoyant force acting on her is:
सही उत्तर: ग) greater than her weight
According to Archimedes' principle, the buoyant force exerted on an object submerged in fluid is equal to the weight of the fluid displaced by the object. Therefore, the buoyant force is less than her weight.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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If a body falls freely from a height of 10 meters, what is its speed just before it hits the ground? (g = 10 m/s²)
सही उत्तर: क) 4.47 m/s
We can use the equation of motion for free fall: v² = u² + 2as, where v is final velocity, u is initial velocity (0 m/s), a is acceleration (g=10 m/s²), and s is distance (10m). Therefore, v² = 0² + 2 * 10 * 10 = 200. So, v = √200 ≈ 14.14 m/s. This value doesn’t match the options provided which indicates an error in either the question or the available answers.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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A stone of mass 2 kg is dropped from a height of 45 m. Neglecting air resistance, what is its velocity just before hitting the ground? (Take g = 9.8 m/s²)
सही उत्तर: ख) 12.6 m/s
We can use the principle of conservation of energy to solve this problem. Potential energy (PE) at height h = mgh, where m=2kg, g=9.8m/s², and h=45m. PE = (2)(9.8)(45) = 882 J. Kinetic Energy (KE) just before hitting the ground is equal to this potential energy. KE = 1/2 * m * v² , where v is velocity. So, 882 = 1/2 * 2 * v², which gives v² = 882. Hence, v = √882 ≈ 29.7 m/s. The question has an error – the calculated value is not present in the options.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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A uniform beam of length 3m and cross-sectional area 4cm² is placed on a horizontal surface. The pressure applied at the end is 500 N. What is the normal reaction force?
सही उत्तर: ख) 1200 N
The normal reaction force is equal to the pressure multiplied by the area of contact. Here, pressure = 500 N and cross-sectional area = 4 cm² = 4 x 10⁻⁴ m². Therefore, Normal Force = (500 * 4 x 10⁻⁴) N = 200 N. This is most closely related to option '1200N', but that's incorrect. The question might have been designed for some specific context (like a building), which would influence the solution, however this seems like an error.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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The refractive index of a material for red light is 1.5 and for violet light is 1.6. What is the dispersion if violet light bends more than red light?
सही उत्तर: क) 1.0
Dispersion refers to the refractive index variation with wavelength. The given values (1.5 and 1.6) represent the refractive indices for red and violet light respectively. The difference in these indices (1.6-1.5=0.1) is the dispersion. The other options are unrelated to this calculation.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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Which of the following statements accurately describes the concept of potential energy?
सही उत्तर: ख) The energy an object possesses when it is at rest due to its position or condition
Potential energy refers to stored energy due to an object's position or condition (e.g., gravitational potential energy). Option 2 describes Kinetic Energy correctly; options 3 and 4 are misinterpretations of the concept.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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A particle moves with a uniform velocity of 5 m/s along a straight line. It covers a distance of 25 meters in 5 seconds. What is its acceleration?
सही उत्तर: ख) 1 m/s²
The formula relating distance, velocity, and time for uniform motion is: Distance = Velocity × Time. Rearranging this to find the acceleration gives: Acceleration = (Distance / Time) / Velocity = (25m / 5s) / 5m/s = 1 m/s². The most tempting incorrect option is ‘0’ because it suggests constant velocity, which is not the case given that distance and time are changing.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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A block of iron weighs 20 N in air and 16 N in water. What is the volume of the iron block?
सही उत्तर: ग) 40 cm³
The buoyant force on the iron block is the difference between its weight in air and its apparent weight in water. Buoyant Force = 20 N - 16 N = 4 N. The volume of the iron block can be calculated using Archimedes' principle: Buoyant Force = V * ρ_water * g, where V is the volume, ρ_water is the density of water (1000 kg/m³), and g is the acceleration due to gravity (10 m/s²). Solving for V, we get V = Buoyant Force / (ρ_water * g) = 4 N / (1000 kg/m³ * 10 m/s²) = 4 × 10⁻⁴ m³ = 4 cm³.”
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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A car is moving at a constant speed of 60 km/h. The engine is supplying a power of 50 kW. What fraction of the power supplied is being used to overcome friction and air resistance?
सही उत्तर: घ) 0.4
The car's speed is constant, meaning its net force is zero (Newton's first law). This net force is equal to the power supplied minus the power lost due to friction and air resistance. Since the speed is constant, all the power supplied *must* be lost as heat due to these factors. Therefore, the fraction of power lost is 50 kW / 50 kW = 1 (or 100%). However, options must have a value less than 1. An alternative approach would be: speed = 60km/h = 17m/s. Force = 17m/s * 50kg = 850 N. Power supplied = 50 kW= 50,000 W. Power lost = 50,000 - 850 = 49150W . The fraction is 49150 / 50000 = 0.983.”
💬 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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