Doubtly
@Doubtly · Joined Feb 2021
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- A conducting square loop is placed in a magnetic field B with its plane perpendicular to the field. The sides of the loop start shrinking at a constant rate Correct solution is option A ) 2aα B Explaination: "a" at any time "t" , the side of the square a= (a₀-α_t) , where α₀ side at t=0 . at this... 1
- A conducting circular loop made of a thin wire, has area 3.5 x 10–3 m2 and resistance 10Ω . Correct option is A) 0.14 mC Explaination: Q=triangleφ/R=1/10A(B_f-B_i) \\ =1/10×3.5×10⁻³(0.4sinπ/2-0) \\ 1/10×3.5×10⁻³(0.4-0)\\ 1.4×10⁻⁴=0.... 1
- Suppose that f is differentiable for all x and that f’(x) ≤ 2 for all x. If f(1) = 2 and f(4) = 8, then f(2) has the value equal to LMV Theorem for f in [1, 2] forall c in(1, 2) f(2)-f(1)/2-1 =f'(c) ≤ 2 f(2)-f(1) ≤ 2 ⇒ f(2) ≤ 4 ...(1) Again, using LMV Theorem in [2, 4] fo... 1
- When seen from below, the blades of a ceiling fan are seen to be revolving anticlockwise and their speed is decreasing. Correct answer is (B) Angular velocity downwards, angular acceleration upwards. 1
- The system of linear equations x + y + z = 2 , 2x + 3y + 2z = 5 , 2x + 3y + (a2 – 1)z = a + 1 Correct option is inconsistent when |a|= sqrt3 Solution:: D=beginvmatrix 1&1&1\\2&3&2\\ 2 &3 &a²-1 endvmatrix D= 1(3a²-3-6) - 1(2a²-2-4) + 1... 1
- O. Why do we see bands separating in column chromatography? we see bands separating in column chromatography Because , In column chromatography, the solutes get adsorbed on the stationary phase, they... 1
- N. Name the different types of Chromatography and explain the principles underlying them. There are two types of chromatography namely: Liquid chromatography ⇒ separate ions that are dissolved insolvent Gas chromatography ⇒ separa... 2
- M. List the properties of solvents which make them suitable for crystallization The properties of solvents which make them suitable for crystallization are The compound to be crystallized should be least or sparingly sol... 1
- L. Define a. Solvent extraction b. Distillation. Solvent extraction : it is ultimately a process of partitioning between two immiscible solvents, and for its optimization, it is necessary t... 2
- K. What is the difference between simple distillation and fractional distillation? Distillation Fraction distillation Simple distillation is used to separate liquids with boiling point gaps of at least 50 degrees. Fractiona... 1
- J. Define : a. Stationary phase b. Saturated solution Statioanry phase - Stationary phase and mobile phase arr terms related to chromatography. Phase on which the materials to be separated are s... 1
- I. Why should spotting of mixture be done above the level of mobile phase ? In thin-layer chromatography( TLC), the sample mixture should be spotted above the solvent level. It is because if the mixture gets in conta... 1
- H. Which properties of solvents are useful for solvent extraction? Organic compound must be more soluble in the organic solvent, than in water. Solvent should be immiscible with water and be able to form two... 1
- G. Give names of two materials used as stationary phase in chromatography. names of two materials used as stationary phase in chromatography. alumina silica gel 1
- F. What will happen if the upper outlet of the condenser is connected to the tap instead of the lower outlet? It is necessary to cool the condenser with cool water for proper functioning of condenser. If tap is connected to the upper outlet then jack... 2
- Identify the pair whose dimensions are equal The correct option is B. The dimensions of torque and work are equal. Both have dimensions as [ML²T⁻²] Explaination: Work (W) = F.s = Fs cos... 1
- Which of the following physical quantities is an axial vector? Correct option is d) Torque Concept :: Axial vectors are those vectors that represent rotational effect and act along the axis of rotation.... 1
- A rocket is fired vertically with a speed of 5 kms-1 from the earth’s surface. How far from the earth does the rocket go before returning to the earth The correct option is (a) 8.0 ×10⁶ m Video Explaination From physics galaxy https://youtu.be/nz4kjm8L6ZU This video not belong to Brainiak f... 1