भौतिक विज्ञान – Physics MCQ
भौतिक विज्ञान – IT प्रवेश
Physics · IT Entrance – B.Sc. CSIT, BIT & BCA · ३९० प्रश्न
३९० 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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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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A stone is thrown vertically upwards with an initial velocity of 15 m/s. What is the maximum height reached by the stone before it starts to fall back down? (एक ढुङ्गालाई 15 मिटर / सेकन्डको सुरु वेगसँग ऊर्वरोधमाथि थ्रो गरिएको छ। ढुङ्गाले फर्किँदा पहिले उच्चतम गहिराइ कस्तो हुन्छ?)
सही उत्तर: ग) 30.6 m
Using the kinematic equation v² = u² + 2as (where v is final velocity, u is initial velocity, a is acceleration due to gravity (-9.81 m/s²), and s is displacement), we can find the maximum height reached at time t, where v=0. Calculating this gives approximately 25.9m.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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The refractive index of glass with respect to air at a particular temperature is 1.5. What is the apparent depth of a swimming pool if its actual depth is 10 meters? (एक विशेष तापक्रममा गिलासको हावा सम्बर्द्धता 1.5 छ। यदि पूलको वास्तविक गहिराइ 10 मिटर छ भने, दृश्य गहिराइ कस्तो हुन्छ?)
सही उत्तर: ख) 8 meters
The apparent depth is calculated using the formula: Apparent Depth = Actual Depth * (1 - Refractive Index). Option 5, 5 meters, represents this correct calculation. The options of 8, 10 and 12 are incorrect because they don't consider the refraction effect.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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A car travels at a constant speed of 20m/s for 10 seconds and then accelerates uniformly to a speed of 30m/s over the next 5 seconds. What is the average velocity of the car during this entire journey? (एक कारले लगातार 20 मिटर/सेकन्डको गतिमा 10 सेकेन्ड र त्यसपछि 5 सेकेन्ड सम्म समानुपातिक गतिमा 30 मिटर/सेकन्ड सम्म त्वरण गर्दछ। यो सम्पूर्ण यात्रा अवधिमा कारको औसत वेग कस्तो हुन्छ?)
सही उत्तर: घ) 30 m/s
The journey is divided into two parts: constant speed and uniform acceleration. The total distance traveled can be calculated using the average velocity over the entire time (15 seconds) and then converted to velocity. Option 3, 27.5 m/s, is derived by correctly calculating the distances in each phase and averaging them.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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A block of mass 2 kg slides down an inclined plane with an angle of 30 degrees. If the coefficient of kinetic friction between the block and the plane is 0.2, what is the acceleration of the block down the incline? (भौतिक विज्ञानमा 30 को कोणीय कोण भएको आनलाइन तल मा स्लाइड भइरहेको 2 किग्रा भारोन्मेष को एकBlock को त्वरण के हो?)
सही उत्तर: ख) 1.2 m/s²
The acceleration is calculated using sin(30°) = frictional force / (mg cos(30°)). The most tempting option, 0.6 m/s², results from a misapplication of the cosine term. The correct calculation involves resolving forces and correctly applying Newton's second law.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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Which of the following statements regarding the principle of superposition in acoustics is correct? (a) The total sound pressure at any point is the sum of the pressures from individual sources. (b) The sound waves interfere constructively only if they are perfectly in phase. (c) The loudness of a sound decreases proportionally to the distance from the source. (d) The superposition principle applies equally to all types of waves, regardless of their properties.
सही उत्तर: क) (a) The total sound pressure at any point is the sum of the pressures from individual sources.
The principle of superposition states that the resultant wave is the sum of all individual waves present at a point. Therefore, (a) correctly describes this principle. Option (b) refers to constructive interference, and (c) relates to sound intensity decreasing with distance.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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