Practice Questions

Q20.As shown in the figure the voltmeter reads 2 V across 5 Ω resistor. The resistance of the voltmeter is _____ Ω

Q21.A conducting circular loop is placed in a uniform magnetic field of 0. 4 T with its plane perpendicular to the field. Somehow, the radius of the loop starts expanding at a constant rate of 1 mm s−1 . The magnitude of induced emf in the loop at an instant when the radius of the loop is 2 cm will be _______ μV .

Q22.Two long parallel wires carrying currents 8 A and 15 A in opposite directions are placed at a distance of 7 cm from each other. A point P is at equidistant from both the wires such that the lines joining the point P to the wires are perpendicular to each other. The magnitude of magnetic field at P is ______ ×10−6 T. (Given: √2 = 1. 4 )

Q25.An electron revolves around an infinite cylindrical wire having uniform linear charge density 2 × 10-8 C m-1 in circular path under the influence of attractive electrostatic field as shown in the figure. The velocity of electron with which it is revolving is ______________ × 106 m s-1. Given mass of electron = 9 × 10-31 kg

Q25.Two equal positive point charges are separated by a distance 2𝑎. The distance of a point from the centre of the line joining two charges on the equatorial line (perpendicular bisector) at which force experienced by a test charge becomes maximum is 𝑎 The value of 𝑥 is ______. 𝑞0 √𝑥. JEE Main 2023 (01 Feb Shift 1) JEE Main Previous Year Paper

Q26.As shown in the figure, a configuration of two equal point charges 𝑞0 = + 2𝜇C is placed on an inclined plane. Mass of each point charge is 20 g. Assume that there is no friction between charge and plane. For the system of two point charges to be in equilibrium (at rest) the height ℎ= 𝑥× 10-3 m. The value of 𝑥 is 1 Take = 9 × 109 N m2 C-2, 𝑔= 10 m s-2 4𝜋𝜀0 𝑥

Q28.A square loop of side 2 . 0 cm is placed inside a long solenoid that has 50 turns per centimetre and carries a sinusoidally varying current of amplitude 2 . 5 A and angular frequency 700 rad s-1. The central axes of the loop and solenoid coincide. The amplitude of the emf induced in the loop is 𝑥× 10-4 V. The value of 𝑥 is ___________ ( Take, 𝜋= 22 7

Q29.A pole is vertically submerged in swimming pool, such that it gives a length of shadow 2 . 15 m within water when sunlight is incident at an angle of 30° with the surface of water. If swimming pool is filled to a height of ) ________ . 1 . 5 m, then the height of the pole above the water surface in centimeters is (𝑛𝑤= 43 ∘

Q29.As shown in the figure, a combination of a thin plano-concave lens and a thin plano-convex lens is used to image an object placed at infinity. The radius of curvature of both the lenses is 30 cm and refraction index of the material for both the lenses is 1 . 75. Both the lenses are placed at distance of 40 cm from each other. Due to the combination, the image of the object is formed at distance x = ______ cm, from concave lens.

Q29.A point object 𝑂 is placed in front of two thin symmetrical coaxial convex lenses 𝐿1 and 𝐿2 with focal length 24 cm and 9 cm respectively. The distance between two lenses is 10 cm and the object is placed 6 cm away from lens 𝐿1 as shown in the figure. The distance between the object and the image formed by the system of two lenses is _____________ cm

Q33.A litre of buffer solution contains 0. 1 mole of each of NH3 and NH4 Cl. On the addition of 0. 02 mole of HCl by dissolving gaseous HCl , the pH of the solution is found to be _____ × 10−3 (Nearest integer) Given: pKb(NH3) = 4. 745 log 2 = 0. 301 log 3 = 0. 477 T = 298 K]

Q34.The number of species trom the following carrying a single lone pair on central atom Xenon is XeF+5 , XeO3, XeO2 F2, XeF−5 , XeO3 F2, XeOF4, XeF4

Q35.When the hydrogen ion concentration [H+]changes by a factor of 1000 , the value of pH of the solution (1) increases by 1000 units (2) decreases by 3 units (3) decreases by 2 units (4) increases by 2 units

Q35.One mole of an ideal monoatomic gas is subjected to changes as shown in the graph. The magnitude of the work done (by the system or on the system) is _______ J (nearest integer) Given : log 2 = 0.3, ln 10 = 2.3

Q35.Amongst the following, the number of species having the linear shape is XeF2, I+3 , C3O2, I−3 , CO2, SO2, BeCl2 and BCl⊖2

Q36.If the pKa of lactic acid is 5 , then the pH of 0. 005 M calcium lactate solution at 25° C is __________ × 10–1 (Nearest integer)

Q36.For complete combustion of ethene, C2H4( g) + 3O2( g) →2 CO2( g) + 2H2O(l) the amount of heat produced as measured in bomb calorimeter is 1406 kJ mol−1 at 300 K. The minimum value of TΔS needed to reach equilibrium is (−) kJ. (Nearest integer) Given: R = 8. 3 J K−1 mol−1

Q37.One mole of an ideal gas at 350 K is in a 2. 0 L vessel of thermally conducting walls, which are in contact with the surroundings. It undergoes isothermal reversible expansion from 2. 0 L to 3. 0 L against a constant pressure of 4 atm. The change in entropy of the surroundings (ΔS) is _____ J K–1 (Nearest integer) Given: R = 8. 314 J K−1 mol−1 . JEE Main 2023 (12 Apr Shift 1) JEE Main Previous Year Paper

Q46.Solid Lead nitrate is dissolved in 1 litre of water. The solution was found to boil at 100. 15°C. When 0. 2 mol of NaCl is added to the resulting solution, it was observed that the solution froze at −0. 8°C. The solutbility product of PbCl2 formed is _____ ×10−6 at 298 K. (Nearest integer) Given : Kb = 0. 5K kg mol−1 and Kf = 1. 8 kg mol−1 . Assume molality to be equal to molarity in all cases. JEE Main 2023 (29 Jan Shift 1) JEE Main Previous Year Paper

Q46.The total number of stereoisomers for the complex [Cr ( ox ) 2ClBr] 3 – (where ox = oxalate) is (1) 3 (2) 2 (3) 4 (4) 1

Q47.If the boiling points of two solvents X and Y (having same molecular weights) are in the ratio 2: 1 and their enthalpy of vaporizations are in the ratio 1 : 2, then the boiling point elevation constant of X is m times the boiling point elevation constant of Y . The value of m is (nearest integer).

Q54.FeO4 θ EFeO42 - / Fe2 + is x × 10-3 V. The value of x is _______

Q54.(i) X(g) ⇌Y(g) + Z(g) Kp1 = 3 (ii) A(g) ⇌2 B( g) Kp2 = 1 If the degree of dissociation and initial concentration of both the reactants X ( g ) and A ( g ) are equal, then 𝑝1 the ratio of the total pressure at equilibrium is equal to x: 1. The value of x is (Nearest integer) 𝑝2

Q55.The Cl −Co −Cl bond angle values in a fac- [Co (NH3)3 Cl3] complex is/are: (1) 90° & 180° (2) 90° (3) 180° (4) 90° & 120° JEE Main 2023 (30 Jan Shift 2) JEE Main Previous Year Paper

Q55.The total number of chiral compound/s from the following is Q56.25 mL of an aqueous solution of KCl was found to require 20 mL of 1M AgNO3 solution when titrated using K2CrO4 as an indicator. What is the depression in freezing point of KCl solution of the given concentration? (Nearest integer). (Given : Kf = 2 . 0 K kg mol-1 ) Assume 1) 100% ionization and 2) density of the aqueous solution as 1 g mL-1