काठमाडौं विश्वविद्यालय KUUMAT / KU CBT तयारी
काठमाडौं विश्वविद्यालय – KUUMAT / KU CBT
KUUMAT / KU CBT · Kathmandu University (KUUMAT / KU CBT)
३,८४१ प्रश्न उपलब्ध। मोड छान्नुहोस्:
BE/B.Arch प्रवेश: 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 the Bohr model of hydrogen, the frequency of revolution of the electron in the n-th orbit is proportional to:
सही उत्तर: क) 1/n³
f = v/(2πr) with v ∝ 1/n and r ∝ n², so f ∝ 1/n³.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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The kinetic energy of the electron in the ground state of a hydrogen atom is:
सही उत्तर: क) 13.6 eV
In the Bohr model KE = −E = +13.6 eV and PE = 2E = −27.2 eV for the ground state.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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The Paschen series of the hydrogen spectrum lies in the:
सही उत्तर: ख) infrared region
Paschen lines arise from transitions to n = 3 and have wavelengths in the infrared.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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The Compton effect provides evidence for:
सही उत्तर: ग) the particle (photon) nature of radiation
The wavelength shift of X-rays scattered by electrons is explained by treating photons as particles carrying momentum.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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A series LCR circuit driven at a frequency below its resonant frequency behaves as:
सही उत्तर: घ) a capacitive circuit (current leads voltage)
Below resonance X_C = 1/(ωC) exceeds X_L = ωL, so the net reactance is capacitive.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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The reactance of a 0.1 H inductor at 50 Hz is about:
सही उत्तर: घ) 31.4 Ω
X_L = 2πfL = 2π × 50 × 0.1 ≈ 31.4 Ω.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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A transformer does not work on steady DC because:
सही उत्तर: क) a steady current produces no change in magnetic flux, so no emf is induced
Induction requires a changing flux; constant DC gives a constant flux through the secondary.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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Materials suitable for permanent magnets should have:
सही उत्तर: ख) high retentivity and high coercivity
Permanent magnets (e.g. steel, alnico) must retain magnetism and resist demagnetisation.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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The area enclosed by the hysteresis loop (B–H loop) of a ferromagnetic material represents:
सही उत्तर: ग) energy lost per unit volume per cycle of magnetisation
The work done in taking the material round one magnetisation cycle, lost as heat, equals the loop area per unit volume.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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A cyclotron is not suitable for accelerating electrons mainly because electrons:
सही उत्तर: ग) quickly become relativistic and fall out of step with the oscillator
Electrons reach speeds near c at low energy; their mass increases, the cyclotron frequency drops, and they lose resonance with the fixed-frequency oscillator.
💬 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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