इन्जिनियरिङ प्रवेश – Mathematics, Physics, Chemistry, English
इन्जिनियरिङ प्रवेश – Mathematics, Physics, Chemistry, English
Engineering Entrance – Mathematics, Physics, Chemistry & English · ३,८४१ प्रश्न
३,८४१ प्रश्न उपलब्ध। मोड छान्नुहोस्:
इन्जिनियरिङ 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
-
At absolute zero temperature, a pure (intrinsic) semiconductor behaves as:
सही उत्तर: ख) an insulator
At 0 K the valence band is full and the conduction band empty, so there are no free carriers.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
-
The ripple factor of an ideal full-wave rectifier output (without filter) is about:
सही उत्तर: घ) 0.48
γ = √((I_rms/I_dc)² − 1) = √(1.11² − 1) ≈ 0.48 (1.21 for half-wave).
💬 टिप्पणी / गल्ती रिपोर्ट (०)
-
By De Morgan's theorem, the complement of (A + B) equals:
सही उत्तर: क) Ā · B̄
(A + B)′ = A′B′; this is why a NOR gate equals an AND gate with inverted inputs.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
-
The barrier potential of a silicon p–n junction at room temperature is about:
सही उत्तर: घ) 0.7 V
Silicon junctions have about 0.7 V (germanium about 0.3 V); 1.1 eV is silicon's band gap.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
-
Electrons pass undeflected through crossed electric (E) and magnetic (B) fields, both perpendicular to their velocity. Their speed is:
सही उत्तर: घ) E/B
The forces balance when eE = evB, so v = E/B.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
-
The specific charge e/m of the electron, first measured by J. J. Thomson, is about:
सही उत्तर: क) 1.76 × 10¹¹ C/kg
e/m = 1.6 × 10⁻¹⁹/9.1 × 10⁻³¹ ≈ 1.76 × 10¹¹ C/kg (9.58 × 10⁷ C/kg is for the proton).
💬 टिप्पणी / गल्ती रिपोर्ट (०)
-
Millikan's oil-drop experiment established that:
सही उत्तर: क) electric charge is quantised
The charges on the drops were always integral multiples of 1.6 × 10⁻¹⁹ C.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
-
In Rutherford's alpha-scattering experiment, if the kinetic energy of the alpha particles is doubled, their distance of closest approach to the nucleus:
सही उत्तर: ग) is halved
At closest approach K = kZe·2e/r₀, so r₀ ∝ 1/K.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
-
Nuclei that contain the same number of neutrons but different numbers of protons are called:
सही उत्तर: क) isotones
Isotopes have the same Z, isobars the same A, and isotones the same neutron number N.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
-
When a nucleus emits a gamma ray:
सही उत्तर: क) its mass number and atomic number are both unchanged
A γ-ray is a photon emitted when an excited nucleus falls to a lower energy state; no nucleons change.
💬 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।
नमस्ते! पाठ्यक्रम, सामान्य ज्ञान, भाषा परीक्षा वा कुनै प्रश्नको उत्तर बुझ्न सोध्नुहोस्।
AI ले गल्ती गर्न सक्छ। महत्वपूर्ण कुरा आधिकारिक स्रोतमा जाँच्नुहोस्।