Practice Questions

Q49.The least count of a screw guage is 0.01 mm . If the pitch is increased by 75% and number of divisions on the circular scale is reduced by 50% , the new least count will be _____ ×10−3 mm

Q49.Two cars P and Q are moving on a road in the same direction. Accleration of car P increases linearly with time whereas car Q moves with a constant accleration. Both cars cross each other at time t = 0, for the first time. The maximum possible number of crossing(s) (including the crossing at t = 0) is ________.

Q50.The moment of inertia of a solid disc rotating along its diameter is 2.5 times higher than the moment of inertia of a ring rotating in similar way. The moment of inertia of a solid sphere which has same radius as the disc and rotating in similar way, is n times higher than the moment of inertia of the given ring. Here, $\mathrm{n}=_________ Consider all the bodies have equal masses.

Q50.At steady state the charge on the capacitor, as shown in the circuit below, is μC.

Q50.The maximum speed of a boat in still water is 27 km/h. Now this boat is moving downstream in a river flowing at 9 km/h. A man in the boat throws a ball vertically upwards with speed of 10 m/s. Range of the ball as observed by an observer at rest on the river bank, is _______ cm. (Take g = 10 m/s2 )

Q50.Two long parallel wires X and Y , separated by a distance of 6 cm , carry currents of 5A and 4A, respectively, in opposite directions as shown in the figure. Magnitude of the resultant magnetic field at point P at a distance 2025 (22 Jan Shift 2) JEE Main Previous Year Paper of 4 cm from wire Y is x × 10−5 T. The value of x is__________ . Take permeability of free space as μ0 = 4π × 10−7SI units.

Q50.A particle is projected at an angle of 30∘ from horizontal at a speed of 60 m/s. The height traversed by the particle in the first second is h0 and height traversed in the last second, before it reaches the maximum height, is h1 . The ratio h0 : h1 is _________ [Take, g = 10 m/s2 ]

Q50.A physical quantity Q is related to four observables a, b, c, d as follows : Q = ab4cd where, a = (60 ± 3)Pa; b = (20 ± 0.1)m; c = (40 ± 0.2)Nsm−2 and d = (50 ± 0.1)m , then the percentage error in Q is x , where x = ________ . 1000

Q50.The volume contraction of a solid copper cube of edge length 10 cm , when subjected to a hydraulic pressure of 7 × 106 Pa, would be ____ mm3 . (Given bulk modulus of copper = 1.4 × 1011 N m−2 )

Q57. Which among the following react with Hinsberg's reagent? Choose the correct answer from the options given below: (1) A, B and E Only (2) A, C and E Only (3) C and D Only (4) B and D Only

Q71.In Carius method of estimation of halogen, 0.25 g of an organic compound gave 0.15 g of silver bromide (AgBr). The percentage of Bromine in the organic compound is … … ×10−1% (Nearest integer). (Given : Molar mass of Ag is 108 and Br is 80 g mol−1 )

Q71.Xg of benzoic acid on reaction with aq NaHCO3 released CO2 that occupied 11.2 L volume at STP. X is _____ g.

Q71.The number of molecules/ions that show linear geometry among the following is ________ SO2, BeCl2, CO2, N−3 , NO2, F2O, XeF2, NO+2 , I−3 , O3

Q71.The formation enthalpies, ΔHf⊖ for H(g) and O(g) are 220.0 and 250.0 kJ mol−1 , respectively, at 298.15 K , and ΔHf ⊖ for H2O(g) is −242.0 kJ mol−1 at the same temperature. The average bond enthalpy of the O −H bond in water at 298.15 K is __________ kJmol−1 (nearest integer).

Q72.Consider the following reaction occurring in the blast furnace: Fe3O4( s) + 4CO(g) →3Fe(l) + 4CO2( g) ' x ' kg of iron is produced when 2.32 × 103 kgFe3O4 and 2.8 × 102 kgCO are brought together in the furnace. The value of ' x ' is _____. (nearest integer) Given: molar mass of Fe3O4 = 232 g mol−1 molar mass of CO = 28 g mol−1 molar mass of Fe = 56 g mol−1} Q73. 37.8 g N2O5 was taken in a 1 L reaction vessel and allowed to undergo the following reaction at 500 K 2 N2O5( g) ⇌2 N2O4( g) + O2( g) The total pressure at equilibrium was found to be 18.65 bar. Then, Kp = ______ ×10−2 [nearest integer] Assume N2O5 to behave ideally under these conditions. Given: R = 0.082 bar Lmol−1 K−1

Q72.A group 15 element forms dπ −dπ bond with transition metals. It also forms hydride, which is a strongest base among the hydrides of other group members that form dπ −dπ bond. The atomic number of the element is ____.

Q72.The molarity of a 70% (mass / mass) aqueous solution of a monobasic acid (X) is __________ ×10−1 M(Nearest integer) [Given: Density of aqueous solution of (X) is 1.25 g mL−1 Molar mass of the acid is 70 g mol−1 ] 2025 (28 Jan Shift 1) JEE Main Previous Year Paper

Q72.A compound ' X′ absorbs 2 moles of hydrogen and ' X′ upon oxidation with KMnO4 ∣H+ gives The total number of σ bonds present in the compound ' X′ is______

Q72.Given below are some nitrogen containing compounds ∣∣∣ 2025 (29 Jan Shift 1) JEE Main Previous Year Paper Each of them is treated with HCl separately. 1.0 g of the most basic compound will consume _______ mg of HCl. (Given molar mass in gmol−1C : 12, H : 1, O : 16, Cl : 35.5)

Q72.The observed and normal molar masses of compound MX2 are 65.6 and 164 respectively. The percent degree of ionisation of MX2 is … … %. (Nearest integer)

Q72.For the thermal decomposition of N2O5( g) at constant volume, the following table can be formed, for the reaction mentioned below. 2 N2O5( g) →2 N2O4( g) + O2( g) x = … × 10−3 atm [nearest integer] Given : Rate constant for the reaction is 4.606 × 10−2 s−1 .

Q73.During " S " estimation, 160 mg of an organic compound gives 466 mg of barium sulphate. The percentage of – Sulphur in the given compound is _______ %. (Given molar mass in gmol−1 of Ba : 137, S : 32, O : 16 )

Q73.When 81.0 g of aluminium is allowed to react with 128.0 g of oxygen gas, the mass of aluminium oxide produced in grams is_______ - (Nearest integer) Given : Molar mass of Al is 27.0 g mol−1 Molar mass of O is 16.0 g mol−1

Q73. Consider the following sequence of reactions : Molar mass of the product formed (A) is _______ gmol−1 .

Q74.Among the following cations, the number of cations which will give characteristic precipitate in their identification tests with K4 [Fe(CN)6] is _____. Cu2+, Fe3+, Ba2+, Ca2+, NH+4 , Mg2+, Zn2+