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nikhil04
@nikhil04
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Joined: Aug 19, 2020
Last seen: Jan 13, 2022
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Answer to: A compound microscope consists of an objective lens of focal length 1 cm and an eyepiece of focal length 5 cm with a separation of 10 cm.

L = 10 ve = ∞ ue = fe = 5 v0 = 10 - 5 = 5 1/v0 - 1/u0 = 1/f0 1/5 - 1/u0 = 1/1 u0 = - 5/4 cm 5/4 = n/40 n = 50

4 years ago
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Answer to: A beam of electrons of energy E scatters from a target having atomic spacing of 1Å.

2d sinθ = nλ 2d√3/2 = (1)λ d = 1A λ = √3 Å √3 = √150/v V = 50 volt E = 50 eV

4 years ago
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Answer to: In a resonance tube experiment when the tube is filled with water up to a height of 17.0 cm from bottom

(1) 2200 Hz Explanation: λ/2 = 24.5 - 17 = 7.5 cm f = V/λ = 330 x 100/15 = 2200 Hz

4 years ago
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Answer to: A physical quantity z depends on four observables a, b, c and d, as z = a^2b^2/3/√cd^3.

(3) 14.5% Explanation: Δt/t = 2Δa/a + 2/3 Δb/b + 1/2 Δc/c + 3 Δd/d = 2 x 2 + 2/3 x 1.5 + 1/2 x 4 + 3 x 2.5 = 4 + 1 + 2 + 7.5 = 14.5%

4 years ago
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Answer to: A wheel is rotating freely with an angular speed ω on a shaft. The moment of inertia of the wheel is I and the moment of inertia of the shaft

(1) 3/4 Explanation: Iω + 0 = Iωc + 3Iωc ωc = ω/4 Loss of kinetic energy = 1/2Iω2 - 1/2(I + 3I)(ω/4)2 = 1/2Iω2 - 1/2Iω2/4 = 3/8Iω2 Fract...

4 years ago
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Answer to: The value of the acceleration due to gravity is g1 at a height h = R/2 (R = radius of the earth) from the surface of the earth.

(3) 5/9 Explanation: Given that gn = gd GM/(R + h)2 = GM/R3(R - d) GM/(R + R/2)2 = GM/R3(R - d) 4GM/9R2 = GM/R2(1 - d/R) 4/9 = 1 - d/R ...

4 years ago
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Answer to: A galvanometer of resistance G is converted into a voltmeter of range 0 - 1V by connecting a resistance R1 in series with it.

(1) R1 + G Explanation: ig(R1 + g) = 1 ig(R1 + G + R2) = 2 1/R1 + G(R1 + G + R2) = 2 R1 + G + R2 = 2R1 + 2G R2 = R1 + G

4 years ago
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Answer to: A bullet of mass 5 g, travelling with a speed of 210 m/s, strikes a fixed wooden target.

(3) 87.5ºC Explanation: As per given condition 1/2 x 1/2 mv2 = (msΔT) Δt = V2/4s = 210 x 210/4 x 4.2 x 0.3 x 1000 = 87.5ºC

4 years ago
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Answer to: Consider the following equations : 2Fe^2+ + H2O2 → xA + yB (in basic medium)

(i) 2Fe2+ + H2O2 → 2Fe3+ + 2OH- (ii) 2MnO4- + 6H+ + 5H2O2 → Mn2++ 5O2 + 8H2O So sum of (x + y + x1 + y1 + z1) = 2 + 2 + 2 + 5 + 8 = 19

4 years ago
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4 years ago
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Answer to: A 100 mL solution was made by adding 1.43 g of Na2CO3.xH2O. The normality of the solution is 0.1 N.

Equivalent of solute = 0.1 × 0.1 Mole of solute (Na2CO3.xH2O) = [0.1 × 0.1]1/2 Mass of Na2CO3.xH2O = [0.1 × 0.1] 1/2 x [106 + 18x] = 1.43 =>...

4 years ago
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Answer to: The osmotic pressure of a solution of NaCl is 0.10 atm and that of a glucose solution is 0.20 atm.

∏ = iCRT = i [n/V]RT ∏final = (π1V1)+ (π2V2)/V1 + V2 ∏final = (0.1 x 1) + (0.2 x 2)/3 = (0.1 + 0.4)/3 = 0.5/3 = 500/3 x 10-3 atm so X = 167

4 years ago
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Answer to: The number of molecules with energy greater than the threshold energy for a reaction increases fivefold by a rise of temperature from 27ºC to 42ºC.

k = Ae- Ea/RT In(K2/K1) = Ea/R[1/T1 - 1/T2] In(5) = Ea/8.314[1/300 - 1/315] 1.6094 = Ea/8.314[15/300 x 315] Ea = 84297 J

4 years ago
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Answer to: The Crystal Field Stabilization Energy (CFSE) of [CoF3(H2O)3] (Δ0 < P) is :

(1) – 0.4 Δ0 Explanation: [CoF3(H2O)3] Co3+ = 3d64s0 => t2g2,1,1 , eg1,1 CFSE = [-0.4n t2g+ 0.6neg]Δ0 + n(P) = [-0.4 x 4 + 0.6 x 2]Δ0 + 0 ...

4 years ago
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Answer to: A sample of red ink (a colloidal suspension) is prepared by mixing eosine dye, egg white, HCHO and water.

(4) Egg white Explanation: Blue ink is a colloidal sol, so it can be stabilised by material like natural gum or Egg white/albumen.

4 years ago
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Answer to: Five moles of an ideal gas at 1 bar and 298 K is expanded into vacuum to double the volume. The work done is :

(2) Zero Explanation: W = –Pext ΔV In expansion against vacuum Pext = 0 So work done is zero

4 years ago
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Answer to: The processes of calcination and roasting in metallurgical industries, respectively, can lead to:

(3) Global warming and acid rain Explanation: In Calcination and roasting CO2 and SO2 are released which are responsible for Global warning and ac...

4 years ago
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Answer to: The mechanism of action of "Terfenadine" (Seldane) is :

(4) Inhibits the action of histamine receptor Explanation: Seldane act as antihistamines and interfere with the natural action of histamine by com...

4 years ago
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