Doubtly
@Doubtly · Joined Feb 2021
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- The general solution of the differential equation (y^2 – x^3 )dx – xydy = 0 (x ≠ 0) is : The correct option is 2) y²+2x³+cx²=0 Detailed explaination 1
- Let a ∈ (0,π/2) be fixed. If the integral ∫ tan x + tan α/tan x - tan α dx = A(x) cos 2α + B(x) sin 2α + C, where C is a Correct option is (4) x – α and log_e|sin(x – α)| Detailed Explaination: ∫ tan x + tan α/tan x - tan α dx = ∫ sin x /cos x+ sin α/cos α/sin... 1
- A particle is moving along a circular path with a constant speed 30 m/s. Correct Answer is option B) 30sqrt2 https://youtu.be/1hcDKwGYKlE 1
- A coil of inductance 300 mH and resistance 2 is connected to a source of voltage 2 V. Correct answer is option d) 0.1 s Explaination: During growth of charge in an inductance, I = I₀ (1 – e ^(–Rt/L)) or I₀/2 = I₀(1 – e^( –Rt/L... 1
- When current in a coil changes from 5 A to 2 A in 0.1 s, an average voltage of 50 V is produced Correct option is 2) 1.67H Explaination EMF = L × di/dt 50 = L × (5-2)/0.1 = L × 30 L = 5/3 = 1.67 1
- A rectangular loop is present in the magnetic field region of an infinite long wire. Now the loop is being rotated as shown in the figure. option B is correct 1
- 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