प्राविधिक – इलेक्ट्रिकल, मेकानिकल र टेलिकम
प्राविधिक – इलेक्ट्रिकल, मेकानिकल र टेलिकम
Technical – Electrical, Mechanical & Telecom · ४,५०० प्रश्न
४,५०० प्रश्न उपलब्ध। मोड छान्नुहोस्:
इलेक्ट्रिकल र टेलिकम: 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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An ideal transformer has 200 primary turns and 1000 secondary turns. If the primary is supplied at 230 V, the secondary voltage is:
सही उत्तर: ख) 1150 V
V2 = V1 x N2 / N1 = 230 x 1000 / 200 = 1150 V.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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A transformer is not operated on a DC supply mainly because:
सही उत्तर: ग) DC produces no changing flux, so no emf is induced in the secondary
Without changing flux there is no induced emf; the primary, having only low winding resistance, would also draw a heavy current and burn.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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A transformer works on the principle of:
सही उत्तर: ग) mutual induction
An alternating flux produced by the primary links the secondary and induces an emf in it (mutual induction).
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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A balanced three-phase load takes a line current of 10 A from a 400 V supply at 0.8 power factor. The power consumed is about:
सही उत्तर: ख) 5.54 kW
P = sqrt 3 x 400 x 10 x 0.8 = 1.732 x 3200 = 5542 W, about 5.54 kW.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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The total active power of a balanced three-phase load is given by:
सही उत्तर: घ) sqrt 3 V_L I_L cos phi
P = 3 V_ph I_ph cos phi = sqrt 3 V_L I_L cos phi for both star and delta.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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A balanced star-connected supply has a line voltage of 400 V. Its phase voltage is about:
सही उत्तर: क) 231 V
V_ph = V_L / sqrt 3 = 400 / 1.732 = 231 V.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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In a balanced three-phase supply, the phase difference between any two phase voltages is:
सही उत्तर: क) 120°
The three phases are displaced by 360°/3 = 120° electrical.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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In a balanced delta connected three-phase system, the line current is:
सही उत्तर: घ) sqrt 3 times the phase current
In delta, I_L = sqrt 3 I_ph while line voltage equals phase voltage.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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In a balanced star (Y) connected three-phase system, the line voltage is:
सही उत्तर: क) sqrt 3 times the phase voltage
In star, V_L = sqrt 3 V_ph and line current equals phase current.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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The quality factor (Q) of a series RLC circuit at resonance is given by:
सही उत्तर: ख) w0 L / R
Q = X_L / R = w0 L / R; it equals the voltage magnification across L or C at resonance.
💬 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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