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Which of the following reaction produce propane as major product?

Answer: c, d... View Article

Choose the correct option that gives aromatic compound as major product:

Answer: a, b... View Article

With reference to aqua regia, choose the correct option(s):

a) Aqua regia is prepared by mixing conc. HCl and conc. HNO3 in 3: 1 molar ratio. b) Reaction of gold with aqua regia produces an anion having... View Article

A wire of density 9 × 10^–3 kg cm^–3 is stretched between two clamps 1 m apart. The resulting strain in the wire is 4.9 × 10^–4. The lowest frequency of the transverse vibrations in the wire is (Young’s modulus of wire Y = 9 ×10¹⁰ Nm^–2), (to the nearest integer), _______.

Answer: (35)... View Article

a particle of mass m is moving along the x axis with initial velocity it collides elastically with a particle of mass 10 m at rest and then moves with half its initial kinetic energy

Answer: (10) , , --------(i) Also, , , , Now, mv1sin θ1= 10 mv2sin θ2 (u/√2)sin θ1= 10 x (u/√20)sin θ2 sin θ1=(10/√10)sin θ2... View Article

A square shaped hole of side l =a/2 is carved out at a distance d = a/2 from the centre ‘O’ of a uniform circular disk of radius a. If the distance of the centre of mass of the remaining portion from O is– a/X, value of X (to the nearest integer) is _________.

Answer: (23) X= (8 π-2) = 8 x 3.14 -2 = 23.12 Nearest Integer = 23... View Article

An ideal cell of emf 10 V is connected in circuit shown in figure. Each resistance is 2Ω. The potential difference (in V) across the capacitor when it is fully charged is _______.

i1=2 Amp i2=1 Amp VAB = 1 × 2 + 3 × 2 = 8V... View Article

A light ray enters a solid glass sphere of refractive index μ= √3 at an angle of incidence 60°. The ray is both reflected and refracted at the farther surface of the sphere. The angle (in degrees) between the reflected and refracted rays at this surface is ________.

Answer: (90) At S1 1 x sin 600=√3 sin r r=300 r = 30° r1 = 30° {from geometry} As S2√3 sinr1 = 1sin e e = 60° Now, r1 + θ + e =... View Article

The figure shows a region of length ‘l’ with a uniform magnetic field of 0.3 T in it and a proton entering the region with velocity 4 ×10⁵ ms–1 making an angle 60° with the field. If the proton completes 10 revolution by the time it cross the region shown, ‘l’ is close to (mass of proton = 1.67 × 10^–27 kg, charge of the proton = 1.6 × 10^–19 C)

1) 0.11 m 2) 0.22 m 3) 0.44 m 4) 0.88 m Answer: (3) l = 10 × pitch = 10 × vcos 60° ×(2π m/qB) = 10 × v ×(1/2) ×(2πm/qB)... View Article

The height ‘h’ at which the weight of a body will be the same as that at the same depth ‘h’ from the surface of the earth is (Radius of the earth is R and effect of the rotation of the earth is neglected):

1) 2) 3) 4) Answer: (3) R3 = (R – h) (R + h)2 R3 = (R –h)(R2+2h+h2) on solving we get,... View Article

A capillary tube made of glass of radius 0.15 mm is dipped vertically in a beaker filled with methylene iodide (surface tension = 0.05 Nm^–1, density = 667 kg m^–3) which rises to height h in the tube. It is observed that the two tangents drawn from liquid-glass interfaces (from opp. sides of the capillary) make an angle of 60° with one another. Then h is close to (g=10 ms^–2).

1) 0.172 m 2) 0.049 m 3) 0.087 m 4) 0.137 m Answer: (3) =0.087 m... View Article

An ideal gas in a closed container is slowly heated. As its temperature increases, which of the following statements are true?

(A) the mean free path of the molecules decreases. (B) the mean collision time between the molecules decreases. (C) the mean free path... View Article

A 10 μF capacitor is fully charged to a potential difference of 50V. After removing the source voltage it is connected to an uncharged capacitor in parallel. Now the potential difference across them becomes 20 V. The capacitance of the second capacitor is:

1) 15 μF 2) 20 μF 3) 10 μF 4) 30 μF Answer: (1) C1 = 10 μF Vf =20V 500/(C1+C2) =20 500/(10+C2) =20 (10+C2) =(500/20) =25 C2= 15 μF... View Article

a charge q is distributed over two concentric conducting thin spherical shells radii r and

1) 2) 3) 4) Answer: (2) Q1= σ4πr2 Q2= σ4πR2 Q=σ4π(R2+r2) , , , ,... View Article

When the temperature of a metal wire is increased from 0°C to 10°C, its length increases by 0.02%. The percentage change in its mass density will be closest to:

1) 0.06 2) 0.008 3) 2.3 4) 0.8 Answer: (1) ∆l / l = ∝∆t ℓ = m / v ∆ ℓ / ℓ = ∆m / m - ∆v / v Here, ∆ m / m = 0 ∆... View Article

In a hydrogen atom the electron makes a transition from (n + 1)^th level to the nth level. If n>>1, the frequency of radiation emitted is proportional to:

1) 1/n2 2) 1/n 3) 1/n3 4) 1/n4 Answer: (3) If n≥1 v ∝(1/n3)... View Article

A heat engine is involved with exchange of heat of 1915 J, –40J, + 125J and –QJ, during one cycle achieving an efficiency of 50.0%. The value of Q is:

1) 980 J 2) 640 J 3) 40 J 4) 400 J Answer: (1) 1020= 1915 -40+125 –Q Q= 980 J... View Article

In a Young’s double slit experiment, 16 fringes are observed in a certain segment of the screen when light of wavelength 700 nm is used. If the wavelength of light is changed to 400 nm, the number of fringes observed in the same segment of the screen would be:

1) 28 2) 24 3) 30 4) 18 Answer: (1)... View Article

This displacement time graph of a particle executing S.H.M. is given in figure : (sketch is schematic and not to scale)

Which of the following statements is/are true for this motion? (A) The force is zero at t = 3T/4 (B) The acceleration is maximum at t=T... View Article

An inductance coil has a reactance of 100 Ω. When an AC signal of frequency 1000 Hz is applied to the coil, the applied voltage leads the current by 45°. The self-inductance of the coil is:

1) 6.7 × 10–7 H 2) 5.5 × 10–5 H 3) 1.1 × 10–1 H 4) 1.1 × 10–2 H Answer: (4) L-R circuit Tan450 = XL/R ⇒ XL= R Now Or =... View Article