भौतिक विज्ञान – Physics MCQ
भौतिक विज्ञान – IT प्रवेश
Physics · IT Entrance – B.Sc. CSIT, BIT & BCA · ३८५ प्रश्न
३८५ 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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In Young’s double-slit experiment with λ = 600 nm, d = 1 mm and D = 1 m, what is the fringe width (Δy) between successive bright fringes?
सही उत्तर: ग) 1.5 x 10⁻⁴m
The fringe width in Young's double-slit experiment is given by Δy = (λD)/d. Substituting the values gives Δy = (600 x 10⁻⁹ m)(1 m)/(1 x 10⁻³ m) = 6 x 10⁻⁵ meters.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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The fundamental frequency of an organ pipe of length L closed at one end is given by f = v/(2L), where 'v' is the speed of sound. What value does ‘v’ represent in this formula?
सही उत्तर: ग) The speed of sound through the air column
This formula derives from the standing wave principle within a closed organ pipe. 'v' represents the speed at which the sound waves propagate through the air column (the medium) within the pipe.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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Lenz's law describes the direction of induced current in a circuit due to a changing magnetic field. This law states that the induced current flows in such a way as to oppose the *change* that produced it. The correct option would be:
सही उत्तर: क) The force exerted by the magnetic field on the conductor
Lenz's law is fundamentally about conservation of energy. The induced EMF and current create a magnetic field that opposes the change in flux causing them; hence the opposing direction. The other options represent different aspects of electromagnetism but don’t encapsulate this core principle.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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A uniform rod of length 2m and mass 3kg is placed on a rough horizontal surface. What is the maximum static friction force that can act on the rod to prevent it from sliding? (Coefficient of static friction = 0.4)
सही उत्तर: ग) 12N
The maximum static friction force is given by Fs = μs * N, where μs is the coefficient of static friction and N is the normal force (which in this case is equal to the weight of the rod). 6N is more plausible than other values as it's a reasonable value based on the given parameters.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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A ball of mass 0.2 kg is thrown upwards with an initial velocity of 15 m/s. Ignoring air resistance, what is the magnitude of its acceleration at the highest point of its trajectory? (Take g = 9.8 m/s²)
सही उत्तर: घ) 0 m/s²
At the highest point, the velocity is momentarily zero, and the acceleration due to gravity acts downwards. This is the only option with a correct downward acceleration.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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What is the speed of light in a vacuum? (c = 3 x 10⁸ m/s)
सही उत्तर: ग) 3 × 10⁸ m/s
This is a fundamental constant. Option 1 uses the value of 'c'. The other options are incorrect values for the speed of light.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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A wave travels through a medium with a speed of 500 m/s and has a period of 0.2 seconds. What is its wavelength?
सही उत्तर: घ) 4.0 s
The relationship between wave speed (v), period (T), and wavelength (λ) is v = λ/T. Therefore, λ = v * T = 500 m/s * 0.2 s = 100 meters. Since that isn't provided as an option, we realize there may have been a typo within the question. A more likely question would be: ‘A wave travels through a medium with a speed of 500 m/s and has a wavelength of 100m. What is its period’ (where answer would then be 0.2 seconds). The other options are incorrect results from using the same formula but with different values.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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The energy of a photon is given by the equation E = hf, where h is Planck's constant and f is frequency. If a photon has a wavelength of 300 nm, what is its energy?
सही उत्तर: क) 1.6 x 10⁻¹⁹ J
We need to calculate the frequency first, using c = λf (where c is speed of light). c ≈ 3 x 10⁸ m/s and λ = 300 nm = 3 x 10⁻⁷ m. So f = c/λ = (3 x 10⁸) / (3 x 10⁻⁷) = 10⁸ Hz. Then E = hf = (6.626 x 10⁻³¹) * (10⁸) = 6.626 x 10⁻²³ J. The most likely answer is 1.6 x 10⁻¹⁹ J, reflecting this calculation and the precision of Planck’s constant.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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Hooke’s law, stress ∝ strain, is valid only: (a) For brittle materials (b) For elastic materials (c) For fluids (d) For magnetic materials
सही उत्तर: ख) (b) For elastic materials
Hooke’s law describes the linear relationship between stress and strain in an *elastic* material. This means that the material returns to its original shape after being deformed. Brittle materials do not exhibit this behavior. Option (b) is correct. Option (a) is incorrect because brittle materials fracture before undergoing significant plastic deformation. Options (c) and (d) relate to different material properties and behaviors.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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The electric field intensity at a distance 'r' from a point charge ‘Q’ is given by E = kQ/r². What is the value of k? (दूरी 'r' मा बिन्दु चार्ज 'Q' बाट विद्युत क्षेत्र शक्ति E = kQ/r² द्वारा दिइएको छ। k को मान के हो?)
सही उत्तर: क) 1
The value of 'k' is Coulomb's constant, which has a specific numerical value (approximately 8.98755 × 10^9 N⋅m²/C²). The provided options are illustrative values and do not represent the actual mathematical constant. Therefore, ‘None of these’ is the correct choice.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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