Doubtly
@Doubtly · Joined Feb 2021
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- Ceric ammonium nitrate and CHCl3/alc. KOH are used for the identification of functional groups The correct answer is option A) Alcohol and amine Solution : Ceric ammonium nitrate and CHCl₃/alc. KOH are used for the identification of fu... 1
- Calgon is used for water treatment. Which of the following statements is NOT true about Calgon? The correct answer is opion A) Calgon contains the 2ⁿd most abundant element by weight in the earth's crust EXplaination :: Order of abundan... 1
- The nature of charge on resulting colloidal particles when FeCl3 is added to excess of hot water is: The correct option is A) positive Explaination :: A positively charged sol of hydrated ferric oxide is formed due to the adsorption of Fe³⁺... 1
- For octahedral Mn(II) and tetrahedral Ni(II) complexes, consider the following statements: The correct answer is b) (I), (II) and (III) only {answer by NTA} Explaination :: 1
- An open beaker of water in quilibrium with water vapour is in a sealed container. When a few grams of glucose Answer: (1) the rate at which water molecules leave the solution decreases At equilibrium, the rate of evaporation (water molecules leaving... 1
- Rate of formation of SO3 in the following reaction 2SO2 + O2 → 2SO3 is 100 g min–1. The correct answer is D) 20 g/min Solution :: dover dt [SO₃]=100 g/min =100over80mole/min =1.25 mole/min -1over2dover dt[SO₂] [SO₃]=-dover d... 1
- Draw the energy band diagram when intrinsic semiconductor (Ge) is doped with impurity atoms of Antimony (Sb). Answer :diagram: 2
- A particle of mass m with an initial velocity collides perfectly elastically with a mass 3 m at rest. It moves with a velocity The correct answer is option d) v=uover sqrt 2 Explaination :: mui+0=mvj+3mv' v'=uover3i-vover3j 1over2mu²=1over2mv²+1over2(3m)Big(big(uover... 1
- A particle executes simple harmonic motion with an amplitude of 5 cm. When the particle is at 4 cm from the mean position, the magnitude of its velocity The correct option is answer a) 8π/3 EXplaination :: v= w√(A²-x²) --speed Acceleeation a= -ω ²x As |v|=|a| ω =3over4⇒T = 2πover ω = 8πover3 1
- The mass of a spaceship is 1000 kg. It is to be launched from the earth’s surface out into free space. The correct answer is option (a) 6.4 x 10^(10 )Joules Explaination :: The energy required is given by = GMmover R = gR² × mover R (∵ g = GMo... 1
- If the distance between the earth and the sun were half its present value, the number of days in a year would have been The correct answer is 129 days option b Explaination : BY keplers third law T² ∝ R³ therefore ( T₂over T₁)²=( R₂over R₁)³ T_(1 )= 365 days ,... 1
- If the current flowing in a coil is reduced to half of its original value, The Correct option is D) E₂ = 1over4 E_(1 ) Explaination Current is become half of the given value. E=1over2Li² i.e. E₂over E₁=(i₂over i₁)²=... 1
- Evaluate int {root x^2 + a^2} dx solve this question This can be best answer possible https://youtu.be/BmCM98ymuiY This video belongs to ganit yogi if they want we can remove it from here . 2
- Find the value of A and B if int(sinx/sin(x-alpha))dx= Answer: (b) (A, B) = (cosα, sinα) Write x = (x-α) + α , so sin x = sin(x-α)cosα + cos(x-α)sinα. Dividing by sin(x-α) : sin x/sin(x-α) = cosα... 1
- If f(x) = ∫t(sinx - sint)dt for t ∈ [0, x] then (A) f'''(x) + f''(x) Answer: (C) f'''(x) + f'(x) = cos x - 2xsin x Write f(x) = sin x∫₀^x t dt - ∫₀^x tsin t dt = dfracx²2sin x - (sin x - xcos x) . Differentiat... 1
- evaluate int x-1/(x+1)^3 e^x dx {integration question } The correct answer is e^xover (x+1)²+c Explaination: 1
- l,m,n are the pth and rth term of G.P all positive then Correct option is 4) 0 Let x and y are first term and common ratio of GP respectively. first and second row are identical =0 1
- find the value of α for which A2 = B, is The correct answer is option d) no real value Explanation:: 1