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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A coreless induction furnace heats the metal charge by:
सही उत्तर: घ) eddy currents induced in the charge by an alternating magnetic field
The charge acts as the secondary of a transformer whose primary is the water-cooled coil; the induced eddy currents heat it.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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A high-pressure mercury vapour lamp emits light that is:
सही उत्तर: ग) bluish-white
Mercury vapour lamps give a bluish-white light rich in blue-green lines and deficient in red.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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The SI unit of luminance (brightness of a surface as seen by the eye) is:
सही उत्तर: ग) candela per square metre (nit)
Luminance is luminous intensity per unit projected area, measured in cd/m²; lux is the unit of illuminance.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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Which insulation class allows the highest permissible operating temperature among the following?
सही उत्तर: घ) Class H
Class H allows 180 °C, more than F (155 °C), B (130 °C) and A (105 °C).
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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Insulation class B of electrical machines and appliances permits a maximum operating temperature of:
सही उत्तर: ग) 130 °C
Thermal classes: A 105 °C, E 120 °C, B 130 °C, F 155 °C, H 180 °C.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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For a 50 Hz current through the human body from hand to feet, the approximate threshold above which ventricular fibrillation becomes likely is:
सही उत्तर: ग) about 50 mA
About 1 mA is the threshold of perception and about 10 mA the let-go limit, while around 50 mA and above can cause ventricular fibrillation.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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The potential difference between two points on the ground surface one step apart, near an earth electrode carrying fault current, is called the:
सही उत्तर: ग) step voltage
Fault current spreading through the soil creates a voltage gradient; the voltage across a 1 m step is the step voltage.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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The potential difference between a person's hand touching an earthed metal structure and his feet during an earth fault is called the:
सही उत्तर: क) touch voltage
Touch voltage is between hand and feet; step voltage is between two feet one step apart on the ground.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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Type B miniature circuit breakers trip magnetically (instantaneously) at about:
सही उत्तर: ग) 3 to 5 times the rated current
Type B: 3–5 In (resistive/domestic loads), Type C: 5–10 In, Type D: 10–20 In.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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A 'Class I' electrical appliance protects the user against electric shock mainly by:
सही उत्तर: घ) basic insulation plus connection of its exposed metal parts to protective earth
Class I relies on earthing of exposed conductive parts so a fault operates the protective device; Class II uses double insulation.
💬 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।
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