Practice Questions

Q30.A transistor is used in common-emitter mode in an amplifier circuit. When a signal of 10 mV is added to the base-emitter voltage, the base current changes by 10μA and the collector current changes by 1. 5 mA . The load resistance is 5kΩ . The voltage gain of the transistor will be _____ .

Q30.A student in the laboratory measures thickness of a wire using screw gauge. The readings are 1. 22 mm, 1. 23 mm, 1. 19 mm and 1. 20 mm . The percentage error is 121x % . The value of x is _____ .

Q30.The height of a transmitting antenna at the top of a tower is 25 m and that of receiving antenna is, 49 m. The maximum distance between them, for satisfactory communication in LOS (Line-Of-Sight) is K√5 × 102 m. The value of K is _____ . (Assume radius of Earth is 64 × 105 m) [Calculate upto nearest integer value]

Q30.The required height of a TV tower which can cover the population of 6 . 03 lakh is ℎ. If the average population density is 100 per square km and the radius of earth is 6400 km, then the value of ℎ will be _____ m.

Q31.Production of iron in blast furnace follows the following equation Fe3 O4(s) + 4 CO(g) →3 Fe(l) + 4 CO2(g) when 4. 640 kg of Fe3 O4 and 2. 520 kg of CO are allowed to react then the amount of iror (in g) produced is : [Given: Molar Atomic mass (gmol−1) : Fe = 56 Molar Atomic mass (gmolm−1) : O = 16 Molar Atomic mass (gmolm−1) : C = 12] (1) 1400 (2) 2200 (3) 3360 (4) 4200

Q31.Given two statements below : Statement I : In Cl2 molecule the covalent radius is double of the atomic radius of chlorine. Statement II : Radius of anionic species is always greater than their parent atomic radius. JEE Main 2022 (26 Jul Shift 1) JEE Main Previous Year Paper Choose the most appropriate answer from options given below (1) Both Statement I and Statement II are correct. (2) Both Statement I and Statement II are incorrect. (3) Statement I is correct but Statement II is (4) Statement I is incorrect but Statement II is incorrect. correct.

Q31. N2(g) + 3H2(g) ⇌2 NH3(g) 20 g 5 g Consider the above reaction. If 20g of dinitrogen reacts with 5g of dihydrogen, then the limiting reagent of the reaction and number of moles of NH3 formed respectively are (1) H2, 1. 42 moles (2) H2, 0. 71 moles (3) N2, 1. 42 moles (4) N2, 0. 71 moles

Q31.The minimum energy that must be possessed by photons in order to produce the photoelectric effect with platinum metal is: [Given: The threshold frequency of platinum is 1 . 3 × 1015 s-1 and h = 6 . 6 × 10-34Js] (1) 8 . 58 × 10-19J (2) 9 . 76 × 10-20J (3) 3 . 21 × 10-14J (4) 6 . 24 × 10-16J

Q31.Given below are two statements : one is labelled as Assertion and the other is labelled as Reason. Assertion: The ionic radii of O2− and Mg2+ are same. JEE Main 2022 (27 Jun Shift 1) JEE Main Previous Year Paper Reason: Both O2− and Mg2+ are isoelectronic species. In the light of the above statements, choose the correct answer from the options given below. (1) Both Assertion and Reason are true and Reason is (2) Both Assertion and Reason are true but Reason is the correct explanation of Assertion. not the correct explanation of Assertion. (3) Assertion is true but Reason is false. (4) Assertion is false but Reason is true.

Q31.Hemoglobin contains 0 . 34% of iron by mass. The number of Fe atoms in 3 . 3 g of hemoglobin is (Given : Atomic mass of Fe is 56u, NA in6 . 022 × 1023 mol-1) (1) 1 . 21 × 105 (2) 12 . 0 × 1016 (3) 1 . 21 × 1020 (4) 3 . 4 × 1022

Q31.Which of the following pair is not isoelectronic species? (Atomic numbers Sm = 62; Er = 68; Yb = 70; Lu = 71; Eu = 63; Tb = 65; Tm= 69 ) (1) Sm2+ and Er3+ (2) Yb2+ and Lu3+ (3) Eu2+ and Tb4+ (4) Tb2+ and Tm4+

Q31.A commercially sold conc. HCl is 35% HCl by mass. If the density of this commercial acid is 1. 46 g/ mL , the molarity of this solution is : (Atomic mass : Cl = 35. 5 amu, H = 1 amu ) (1) 10. 2 M (2) 14. 0 M (3) 12. 5 M (4) 18. 2 M

Q31.Compound A contains 8. 7% Hydrogen, 74% Carbon and 17. 3% Nitrogen. The molecular formula of the compound is, Given : Atomic masses of C, H and N are 12, 1 and 14 amu respectively. The molar mass of the compound A is 162 g mol−1 . (1) C4H6N2 (2) C2H3N (3) C5H7N (4) C10H14N2

Q31.If a rocket runs on a fuel (C15H30) and liquid oxygen, the weight of oxygen required and CO2 released for every litre of fuel respectively are : (Given : density of the fuel is 0. 756 g/ mL ) (1) 1188 g and 1296 g (2) 2376 g and 2592 g (3) 2592 g and 2376 g (4) 3429 g and 3142 g

Q31.The first ionization enthalpies of Be, B, N and O follow the order (1) B < Be < O < N (2) O < N < B < Be (3) Be < B < N < O (4) B < Be < N < O JEE Main 2022 (25 Jul Shift 2) JEE Main Previous Year Paper

Q32.Cs + O2g →CO2g + 400 kJ 1 Cs + 2O2g →COg + 100 kJ When coal of purity 60% is allowed to burn in presence of insufficient oxygen, 60% of carbon is converted into ' CO' and the remaining is converted into 'CO2'. The heat generated when 0 . 6 kg of coal is burnt is (1) 1600 kJ (2) 3200 kJ (3) 4400 kJ (4) 6600 kJ

Q32.Identify the incorrect statement for PCl5 from the following. (1) In this molecule, orbitals of phosphorous are (2) The geometry of PCl5 is trigonal bipyramidal. assumed to undergo sp3 d hybridization. (3) PCl5 has two axial bonds stronger than three (4) The three equatorial bonds of PCl5 lie in a plane. equatorial bonds.

Q32.Which of the following statements are correct? (A) The electronic configuration of Cr is [Ar] 3d54s1 . (B) The magnetic quantum number may have a negative value. (C) In the ground state of an atom, the orbitals are filled in order of their increasing energy order. (D) The total number of nodes are given by n −2. Choose the most appropriate answer from the options given below. (1) (A), (C) & (D) only (2) (A) & (B) only (3) (A) & (C) only (4) (A), (B) & (C) only

Q32.Match List I with List II List-I List-II A XeO3 I sp3 d ; linear B XeF2 II sp3 ; pyramidal C XeOF4 III sp3 d3 ; distorted octahedral D XeF6 IV sp3 d2 ; square pyramidal Choose the correct answer from the options given below (1) A −II, B −IV, C −III, D −I (2) A −IV, B −II, C −III, D −I (3) A −II, B −I, C −IV, D −III (4) A −IV, B −II, C −I, D −III

Q32.The first ionization enthalpy of Na, Mg and Si, respectively, are: 496, 737 and 786 kJ mo 1−1 . The first ionization enthalpy (kJmol−1) of Al is (1) 487 (2) 768 (3) 577 (4) 856

Q32.Match List - I with List - II. List-I List-II (Compound) (Shape) A BrF5 I bent B [CrF6]3− II square pyramidal C O3 III trigonal bipyramidal D PCl5 IV octahedral Choose the correct answer from the options given below (1) (A) −(I), (B) −(II), (C) −(III), (D) −(IV) (2) (A) −(IV), (B) −(III), (C) −(II), (D) −(I) (3) (A) −(II), (B) −(IV ), (C) −(I), (D) −(III) (4) (A) −(III), (B) −(IV), (C) −(II), (D) −(I)

Q32.Which one of the following techniques is not used to spot components of a mixture separated on thin layer chromatographic plate? (1) I2 (Solid) (2) U.V. Light (3) Visualisation agent as a component of mobile (4) Spraying of an appropriate reagent phase

Q32.Which of the following is the correct plot for the probability density ψ2(r) as a function of distance ′r′ of the electron form the nucleus for 2s orbital? JEE Main 2022 (29 Jun Shift 2) JEE Main Previous Year Paper (1) (2) (3) (4)

Q32.Based upon VSEPR theory, match the shape (geometry) of the molecules in List-I with the molecules in List - II and select the most appropriate option. List-I List-II (Shape) (Molecules) A T-shaped I. XeF4 B Trigonal planar II. SF4 C Square planar III. ClF3 D See-saw IV. BF3 (1) (A) −(I), (B) −(II), (C) −(III), (D) −(IV) (2) (A) −(III), (B) −(IV), (C) −(I), (D) −(II) (3) (A) −(III), (B) −(IV), (C) −(II), (D) −(I) (4) (A) −(IV), (B) −(III), (C) −(I), (D) −(II)

Q32.In which of the following pairs, electron gain enthalpies of constituent elements are nearly the same or identical? (A) Rb and Cs (B) Na and K (C) Ar and Kr (D) I and At Choose the correct answer from the options given below (1) A & B only (2) B & C only (3) A & C only (4) C & D only