चिकित्सा शिक्षा आयोग (CEE) बीडीएस प्रवेश परीक्षा तयारी
चिकित्सा शिक्षा आयोग (CEE) – बीडीएस प्रवेश परीक्षा
CEE – BDS Entrance · Medical Education Commission – CEE
२,०३९ प्रश्न उपलब्ध। मोड छान्नुहोस्:
MBBS/BDS/Nursing 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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Plaster of Paris is used in hospitals for making casts to support fractured bones because, when mixed with water, it:
सही उत्तर: घ) sets into a hard mass of gypsum
CaSO₄·½H₂O takes up water and sets into hard gypsum, CaSO₄·2H₂O, with a slight expansion that gives a firm cast.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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For a reaction with the rate law rate = k[A]^(1/2)[B]^(3/2), the overall order of the reaction is:
सही उत्तर: ग) 2
Overall order = sum of the exponents = 1/2 + 3/2 = 2.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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Alum or ferric chloride applied to a small cut stops bleeding because it:
सही उत्तर: ग) coagulates the colloidal blood proteins
Blood is a colloidal sol of negatively charged particles; the highly charged Al³⁺ or Fe³⁺ ions coagulate it and a clot forms (Hardy–Schulze rule).
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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The rate of a reaction doubles when the temperature is raised from 300 K to 310 K. The activation energy of the reaction is about (R = 8.314 J K⁻¹ mol⁻¹):
सही उत्तर: घ) 53.6 kJ/mol
ln 2 = (Ea/R)(1/300 − 1/310), so Ea = 8.314 × 0.693/(1.075 × 10⁻⁴) ≈ 5.36 × 10⁴ J/mol = 53.6 kJ/mol.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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A first-order reaction is 90% complete in 30 minutes. Its half-life is about:
सही उत्तर: क) 9 min
k = (2.303/30) log(100/10) = 0.0768 min⁻¹; t½ = 0.693/k ≈ 9.0 min.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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The quantity of electricity required to reduce 1 mol of MnO₄⁻ to Mn²⁺ is:
सही उत्तर: ख) 5 F
Mn changes from +7 to +2, gaining 5 electrons per ion, so 5 mol of electrons = 5 faradays are needed.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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The oxidation state of chromium in potassium dichromate (K₂Cr₂O₇) is:
सही उत्तर: क) +6
2(+1) + 2x + 7(−2) = 0 gives 2x = 12, so x = +6.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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The oxidation number of sulphur in the peroxodisulphate ion (S₂O₈²⁻), which contains one O–O peroxide link, is:
सही उत्तर: घ) +6
Of the 8 O atoms, 2 are peroxide (−1 each) and 6 are −2: 2x − 2 − 12 = −2, so x = +6 (the formal value +7 ignores the peroxide link).
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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The pH of human blood is kept nearly constant at about 7.4 mainly by the buffer system of:
सही उत्तर: ग) H₂CO₃ and HCO₃⁻
The carbonic acid–bicarbonate pair is the main buffer of blood plasma, keeping its pH near 7.35–7.45.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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The molar solubility of CaF₂ in water at a certain temperature is 2 × 10⁻⁴ mol/L. Its solubility product is:
सही उत्तर: ख) 3.2 × 10⁻¹¹
CaF₂ ⇌ Ca²⁺ + 2F⁻; Ksp = s(2s)² = 4s³ = 4 × (2 × 10⁻⁴)³ = 3.2 × 10⁻¹¹.
💬 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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