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 temperature at which water boils at atmospheric pressure is approximately:
सही उत्तर: घ) 0°C
At standard atmospheric pressure (1 atm), water boils at 100°C. The other options represent different temperatures or states of matter. 373K is the absolute temperature equivalent to 100°C.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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The force acting on a body is inversely proportional to its velocity. If the force is 20 N when the velocity is 2 m/s, what will be the force when the velocity is 4 m/s?
सही उत्तर: ग) 20 N
Let F be the force and v be the velocity. We are given that F ∝ 1/v. This can be written as F = k/v, where k is a constant of proportionality. When F=20N and v=2m/s, we have 20 = k/2 => k = 40. Therefore, when v=4 m/s, F = 40/(4) = 10 N. The incorrect answers arise from incorrectly applying the proportionality.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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A car is moving at a constant speed of 36 km/h. What is its speed in m/s?
सही उत्तर: क) 3.6 m/s
To convert kilometers per hour (km/h) to meters per second (m/s), we multiply by 5/18. Therefore, 36 km/h * (5/18) = 3.6 m/s. The other options are incorrect as they do not correctly perform the conversion.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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The speed of sound in air at a particular temperature is 343 m/s. If the frequency of a sound wave is 440 Hz, what is its wavelength?
सही उत्तर: ख) 0.77 m
The speed of sound (v), frequency (f) and wavelength (λ) are related by the equation v = fλ. Solving for λ, we get λ = v/f = 343m/s / 440 Hz ≈ 0.77 m. This is the correct wavelength based on the given values. The other options reflect incorrect calculations or a misunderstanding of the relationship between these quantities.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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A light bulb is connected to an electrical supply of 230V at a current of 0.5A. Calculate the power dissipated by the bulb in watts.
सही उत्तर: क) 115 W
Power (P) is calculated using the formula P = VI, where V is voltage and I is current. Therefore, P = 230V * 0.5A = 115W. The other options arise from incorrect calculations using the given values.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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The potential difference across a conductor is given by V = IR, where I is the current in amperes and R is the resistance in ohms. If a wire has a resistance of 10 Ω and a current of 2 A flows through it, what is the potential difference across the wire?
सही उत्तर: क) 20 V
This question tests the direct application of Ohm's Law. V = IR means potential difference equals current times resistance. Plugging in the values gives V = 2 A * 10 Ω = 20 V. The other options provide incorrect calculations based on either incorrect values or a misunderstanding of the relationship between voltage, current, and resistance.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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A uniform wooden block of density 800 kg/m³ floats in water with half its volume submerged. What is the density of water?
सही उत्तर: क) 600 kg/m³
The buoyant force acting on the block equals its weight. Since the block floats, its density is less than that of water. The correct answer (800 kg/m³) reflects the given density of the block and the principle of buoyancy. The other options are incorrect as they either assign a value to water or introduce incorrect relationships between volume and density.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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A stone of mass 0.5 kg is attached to a string and whirled in a vertical circle with a radius of 1 meter at a speed of 6 m/s. Neglecting air resistance, what is the tension in the string?
सही उत्तर: क) 2.94 N
The centripetal force acting on the stone is given by F = mv²/r. This force must be provided by the tension in the string. Calculating this gives approximately 2.94 Newtons. The other options are incorrect due to misapplication of the formula or inaccurate calculations.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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The potential energy per unit volume of a gas is given by U(V) = BV^2, where B is a constant. If the temperature of the gas is increased by 10% while maintaining the pressure constant, what will be the percentage change in the potential energy?
सही उत्तर: घ) 20
The potential energy (U) depends on volume (V). Given U = BV^2, when temperature increases by 10% and pressure is held constant, volume also increases proportionally. The new potential energy will be proportional to the new volume which is 1.1 times the original volume. Therefore, the potential energy increases by 1.1 * B * (1.1)^2 = 1.331B, representing an increase of approximately 16%. The most tempting answer (5%) is incorrect because it doesn't account for the proportional change in volume.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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If a body falls from rest, the distance fallen in 2 seconds is 10 meters. What will be the distance fallen in another 2 seconds? (Assume g = 10 m/s²).
सही उत्तर: ख) B. 20 m
Option B, 20m, is correct. This is a problem involving constant acceleration. The distance fallen is proportional to the square of time (d = (1/2)gt²). The first 2 seconds cover 10 meters. Another 2 seconds will cover another 10 meters, thus total distance= 20m.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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