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 refractive index of glass with respect to air is 1.5. This means that light travels at different speeds in glass and air. If the speed of light in air is approximately 3 x 10⁸ m/s, what is the speed of light in glass?
सही उत्तर: घ) 9 x 10⁸ m/s
The refractive index (n) is the ratio of the speed of light in a medium to the speed of light in vacuum. Thus, n = v_glass / v_air, where v_air is approximately 3 x 10⁸ m/s. Therefore, v_glass = n * v_air = 1.5 * (3 x 10⁸) = 4.5 x 10⁸ m/s. A value of 2x10^8 would be incorrect because it doesn't consider the ratio provided in refractive index
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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A uniform rod of length L and mass M is placed in equilibrium on a rough horizontal surface. What fraction of the length L will be in contact with the surface?
सही उत्तर: ख) 0.5
For equilibrium, the forces acting on the rod must balance. The weight (Mg) acts downwards, and the friction force (f) acts upwards. The condition for equilibrium is Mg = fL. Therefore, the fraction of length in contact with the surface is L/L=1 because the entire length has to be in contact. A value of 0.25 or 0.5 would imply a non-uniform distribution of friction – which is incorrect given the problem states a uniform rod
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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The resistance of a wire depends on its length and cross-sectional area. How is this relationship represented mathematically?
सही उत्तर: क) R = L/A
Resistance (R) is directly proportional to the length (L) of the wire and inversely proportional to its cross-sectional area (A). Thus, R = ρL/A, where ρ is resistivity. The equation R= L/A accurately represents this relationship.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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A uniform block of wood floats in equilibrium in a liquid. What can be concluded about the density of the wood and the liquid?
सही उत्तर: ख) The density of the wood is less than the density of the liquid
According to Archimedes' principle, a floating object displaces its weight in the fluid. For equilibrium, the weight of the block must equal the buoyant force, which is equal to the weight of the displaced liquid. This implies that the density of the wood is less than the density of the liquid.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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Which of the following best describes the phenomenon of refraction of light? (Consider a ray of light passing from one medium to another with different refractive indices)
सही उत्तर: ख) Light bends when it passes from one medium to another due to change in speed
Refraction describes the bending of light as it moves between media with different refractive indices. This occurs because the speed of light changes when it enters a new medium. The other options describe reflection, absorption, or the constant speed of light (independent of the medium).
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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A body falls from rest under gravity. What is the velocity of the body after falling a distance ‘h’? (Assume air resistance is negligible)
सही उत्तर: घ) gh/2
The equation of motion for a body falling under constant acceleration due to gravity is h = ut + (1/2)gt², where u is the initial velocity. When u=0, we have h = (1/2)gt², so v = gt (where v is velocity). The other options involve incorrect calculations or assumptions about time.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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The pressure exerted by a column of liquid at a depth ‘h’ in a fluid is given by which formula? (where ρ is density and g is acceleration due to gravity)
सही उत्तर: क) ρgh
The correct formula for pressure exerted by a fluid column is ρgh, where ρ is the density of the fluid, g is the acceleration due to gravity, and h is the height (depth) of the fluid. The other options involve incorrect combinations of these variables.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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The force required to move a body over a distance on a surface is equal to ______.
सही उत्तर: ख) the momentum of the body
According to Newton's second law, the force required to move an object over a distance on a surface is equal to its mass multiplied by the acceleration (F=ma). The other options represent different physical quantities.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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A simple pendulum consists of a mass ‘m’ attached to a string of length ‘l’. The period of oscillation (T) depends on ______.
सही उत्तर: ख) length of the string
The period of a simple pendulum is determined by its physical properties. Specifically, it’s directly proportional to the square root of the length of the string. Changes in mass or temperature would not significantly affect the period.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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The phenomenon of dispersion of white light into its constituent colors by a prism is caused by ______.
सही उत्तर: ग) refraction
Dispersion arises from the fact that each wavelength (color) of light refracts at slightly different angles when passing through the prism. The prism reflects light which causes a separation of colors. Absorption would cause light to disappear, reflection doesn't explain color separation, interference is related to wave overlap.
💬 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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