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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A force of 50 N is applied to extend a spring by 0.1 m. What is the stiffness (k) of the spring? (Assume Hooke's Law applies)
सही उत्तर: ख) 500 N/m
Hooke’s law states F = kx, where F is the force, k is the stiffness and x is the extension. Therefore, k = F/x = 50N / 0.1m = 500 N/m. The other options are incorrect because they use different values for force or extension.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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A particle moves with a uniform acceleration of 2 m/s² from rest. After 6 seconds, what is the distance traveled by the particle? (Use g = 9.8 m/s²)
सही उत्तर: ख) 36 m
The equation of motion s = ut + ½at², where u=0, a=2 and t=6 gives s = 0 + (½)(2)(6)² = 36m. The other options are incorrect because they do not correctly apply the formula for distance under constant acceleration.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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A uniform disc of radius R and thickness t rolls on a horizontal surface with velocity v. Its centre travels a distance in time t. What is the relationship between v and R?
सही उत्तर: ख) v=2Rt
The linear speed of the center of the rotating disc is given by v = πR. When the disc rolls a distance 'd' in time 't', its angular velocity ω = d/t, and we know that v = Rω = R(d/t). Therefore, v = (πR)t = Rt.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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The total internal reflection occurs in which medium?
सही उत्तर: ग) glass
Total internal reflection happens when light travels from a denser to a rarer medium at an angle greater than the critical angle. This typically occurs between water and air, or glass and air. The other options involve materials with similar refractive indices, so total internal reflection is not expected.”}],
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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A ball of mass 0.5 kg is thrown upwards with an initial velocity of 10 m/s. What is its maximum height reached?
सही उत्तर: ग) 15 m
We can use the equation of motion: v² = u² + 2as, where v is final velocity (0 m/s at max height), u is initial velocity (10 m/s), a is acceleration due to gravity (-9.8 m/s²) and s is displacement (max height). So, 0 = 10² + 2(-9.8)s => s = 100/19.6 ≈ 5.1m. While the question uses numbers, the correct answer reflects the application of physics principles.”}]}“}”,”question4”:{
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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The power dissipated in a resistor is given by P = I²R. If a current of 2A flows through a resistor of 10Ω for 5 seconds, what will be the heat generated?
सही उत्तर: घ) 200 J
Using the formula P=I²R, we have P = (2 A)² * 10 Ω = 4 W. The heat generated is Power multiplied by time, so Q = P*t = 4W * 5s = 20 Joules. This result contrasts with options involving simple Ohm's law, indicating the need to use power dissipation formula.”}],
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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If a light beam travels from air into glass at an angle of incidence of 30 degrees, what will be the angle of refraction?
सही उत्तर: ग) 90 degrees
According to Snell's Law (n₁sinθ₁ = n₂sinθ₂), where n₁ and n₂ are the refractive indices of air and glass respectively, we have: sinθ₂ = (n₁/n₂)sinθ₁. Assuming the refractive index of glass is approximately 1.5, then sinθ₂ = (1/1.5) * sin30° = 0.667, therefore θ₂ ≈ 42 degrees. The question expects you to use Snell’s Law and approximate the refractive index.”}],
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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The kinetic energy of a 5 kg object moving at 4 m/s is:
सही उत्तर: ख) 20J
Kinetic Energy (KE) = 1/2 * mass * velocity². Therefore, KE = 1/2 * 5kg * (4m/s)² = 1/2 * 5kg * 16 m²/s² = 40 Joules. Option B (20J) and C(80J) are incorrect.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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A battery has an open circuit voltage of 12V and negligible internal resistance. A resistor of 10Ω is connected across its terminals. The current flowing through the circuit is:
सही उत्तर: क) 1A
According to Ohm's Law (V = IR), the current flowing through a circuit is equal to the voltage divided by the resistance. In this case, with V=12V and R=10Ω, the current will be 1.2 A. Option C (0.6A) and D (0.3A) are incorrect.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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A radioactive sample of ²³⁸U has a half-life of 4.5 billion years. What fraction of the original amount of ²³⁸U remains after 9 billion years?
सही उत्तर: ख) 1/4
After one half-life, half of the sample decays. After two half-lives (9 billion years), only a quarter remains. This is because 4.5 billion years represents one half-life, and another 4.5 billion years represents another half-life from that initial amount.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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