विज्ञान – Science MCQ
विज्ञान – डिप्लोमा प्रवेश
Science · CTEVT Diploma Engineering Entrance · ४०५ प्रश्न
४०५ प्रश्न उपलब्ध। मोड छान्नुहोस्:
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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A student can read a book clearly but cannot see the writing on a distant blackboard. The defect and its correcting lens are:
सही उत्तर: ख) Myopia, concave lens
Not seeing far objects clearly is myopia (short-sightedness), corrected with a diverging concave lens. Hypermetropia is the opposite defect, corrected with a convex lens.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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A concave mirror has a radius of curvature of 30 cm. Its focal length is:
सही उत्तर: घ) 15 cm
For a spherical mirror f = R/2 = 30/2 = 15 cm. 60 cm comes from wrongly doubling R.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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An object placed 20 cm from a convex lens forms a real image 60 cm from the lens. The magnitude of magnification is:
सही उत्तर: घ) 3
Magnification m = v/u = 60/20 = 3, so the image is three times the size of the object. 1/3 results from inverting the ratio.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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The power of a convex lens of focal length 25 cm is:
सही उत्तर: ख) +4 D
P = 1/f (in metres) = 1/0.25 = +4 D. The sign is positive for a convex (converging) lens; −4 D would be a concave lens.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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An object is placed 15 cm in front of a convex lens of focal length 10 cm. The image is formed at:
सही उत्तर: ख) 30 cm on the other side of the lens
Using 1/v − 1/u = 1/f with u = −15 cm: 1/v = 1/10 − 1/15 = 1/30, so v = +30 cm (real image). An object between F and 2F gives a real image beyond 2F.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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The refractive index of glass is 1.5. If light travels at 3 × 10⁸ m/s in vacuum, its speed in glass is:
सही उत्तर: ग) 2 × 10⁸ m/s
v = c/n = 3 × 10⁸ / 1.5 = 2 × 10⁸ m/s. Light slows down in a denser medium, so 4.5 × 10⁸ m/s is impossible.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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A person standing in front of a cliff hears the echo of a shout 2 s later. If sound travels at 340 m/s, the distance to the cliff is:
सही उत्तर: ग) 340 m
Sound travels to the cliff and back, so distance = (v × t)/2 = (340 × 2)/2 = 340 m. 680 m is the total to-and-fro path.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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A temperature of 77 °F is equal to:
सही उत्तर: क) 25 °C
C = (F − 32) × 5/9 = (77 − 32) × 5/9 = 25 °C. 45 is (F − 32) before multiplying by 5/9.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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2 kg of water at 60 °C is mixed with 1 kg of water at 30 °C. Neglecting heat loss, the final temperature is:
सही उत्तर: ग) 50 °C
2(60 − T) = 1(T − 30) gives 3T = 150, T = 50 °C. 45 °C is the simple average, which is wrong because the masses are unequal.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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1 kg of water at 80 °C is mixed with 1 kg of water at 20 °C. Neglecting heat loss, the final temperature is:
सही उत्तर: ख) 50 °C
Heat lost = heat gained: 1 × c × (80 − T) = 1 × c × (T − 20), so T = 50 °C. For equal masses of the same liquid the final temperature is the simple average.
💬 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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