Practice Questions

Q29.In a common emitter amplifier circuit using an 𝑛- 𝑝- 𝑛 transistor, the phase difference between the input and the output voltages will be: (1) 180° (2) 45° (3) 90° (4) 135°

Q30.A signal is to be transmitted through a wave of wavelength λ, using a linear antenna. The length l of the antenna and effective power radiated Peff will be given, respectively, as- ( K is a constant of proportionality) (1) λ 8 , Peff = K( λl ) (2) 16λ , Peff = K( λl ) 3 (3) λ 1 (4) λ, Peff = K( λl ) 2 5 , Peff = K( λl ) 2

Q30.A signal of frequency 20 kHz and peak voltage of 5 Volt is used to modulate a carrier wave of frequency 1. 2 MHz and peak voltage 25 Volts . Choose the correct statement. (1) Modulation index = 5 , side frequency bands are (2) Modulation index = 5 , side frequency bands are at 1400 kHz and 1000 kHz. at 21. 2 kHz and 18. 8 kHz. (3) Modulation index = 0. 2 , side frequency bands (4) Modulation index = 5 , side frequency bands are are at 1220 kHz and 1180 kHz. at 24. 2 kHz and 18. 8 kHz.

Q30.In amplitude modulation, the sinusoidal carrier frequency used is denoted by 𝜔𝑐 and the signal frequency is denoted by 𝜔𝑚 . The bandwidth Δ𝜔𝑚 of the signal is such that Δ𝜔𝑚≪𝜔𝑐. Which of the following frequencies is not contained in the modulated wave? (1) 𝜔𝑐- 𝜔𝑚 (2) 𝜔𝑚 (3) 𝜔𝑐 (4) 𝜔𝑚+ 𝜔𝑐 Q31.1 gram of a carbonate M2CO3 on treatment with excess HCl produces 0.01186 moles of CO2 . The molar mass of M2CO3 in gmol-1 is: (1) 84.3 (2) 118.6 (3) 11.86 (4) 1186

Q31.Excess of NaOH (aq) was added to 100 mL of FeCl3 (aq) resulting into 2. 14 g of Fe (OH)3 . The molarity of FeCl3(aq) is: (Given the molar mass of Fe = 56 g mol−1 and molar mass of Cl = 35 .5 g mol−1 ) (1) 0. 3 M (2) 0. 2 M (3) 0. 6 M (4) 1. 8 M JEE Main 2017 (08 Apr Online) JEE Main Previous Year Paper

Q31.What quantity (in mL ) of a 45% acid solution of a mono-protic strong acid must be mixed with a 20% solution of the same acid to produce 800 mL of a 29. 875% acid solution? (1) 316 (2) 320 (3) 325 (4) 330

Q32.If the shortest wavelength in Lyman series of hydrogen atom is A, then the longest wavelength in Paschen series of He+ is (1) 5A (2) 36A 9 7 (3) 36A (4) 9A 5 5

Q32.The electron in the hydrogen atom undergoes transition from higher orbitals to orbital of radius 211. 6 pm . This transition is associated with (1) Lyman series (2) Balmer series (3) Brackett series (4) Paschen series

Q32.The most abundant elements by mass in the body of a healthy human adult are: Oxygen (61.4%); Carbon (22.9%), Hydrogen (10.0%); and Nitrogen (2.6%). The weight which a 75kg person JEE Main 2017 (02 Apr) JEE Main Previous Year Paper would gain if all 1𝐻 atoms are replaced by 2𝐻 atoms is: (1) 37.5 kg (2) 7.5 kg (3) 10 kg (4) 15 kg

Q33.Which of the following is paramagnetic? (1) CO (2) NO+ (3) O2−2 (4) B2

Q33.The electronic configuration with the highest ionization enthalpy is: (1) [Ar] 3d10 4s2 4p3 (2) [Ne]3s2 3p1 (3) [Ne] 3s2 3p3 (4) [Ne] 3s2 3p2

Q33.Among the following species which option contains all isoelectronic species? (1) 𝑂-, 𝐹-, 𝑁𝑎, 𝑀𝑔+ (2) 𝑂2 - , 𝐹-, 𝑁𝑎, 𝑀𝑔2 + (3) 𝑂-, 𝐹-, 𝑁𝑎+, 𝑀𝑔2 + (4) 𝑂2 - , 𝐹-, 𝑁𝑎+, 𝑀𝑔2 +

Q34.The group having triangular planar structure is: (1) BF3, NF3, CO2−3 (2) CO2−3 , NO−3 , SO3 (3) NH3, SO3, CO2−3 (4) NCl3, BCl3, SO3

Q34. sp3 d2 hybridization is not displayed by (1) SF6 (2) BrF5 (3) PF5 (4) [CrF6]3−

Q34.The radius of the second Bohr orbit for hydrogen atom is (Planck's constant, ( h ) = 6 .6262 × 10−34Js; mass of electron = 9 .1091 × 10-31kg; charge of electron = 1 .60210 × 10-19C; permittivity of vacuum, ( ∈0 ) = 8 .854185 × 10-12kg-1m-3A2) (1) 4 .76 Å (2) 0 .529 Å (3) 2 .12 Å (4) 1 .65 Å

Q35.Among the following, the incorrect statement is: (1) at low pressure, real gases show ideal behaviour. (2) at very low temperature, real gases show ideal behaviour. (3) at Boyle's temperature, real gases show ideal (4) at very large volume, real gases show ideal behaviour. behaviour.

Q35.Which of the following species is not paramagnetic? (1) CO (2) O2 (3) B2 (4) NO

Q35.The increasing order of the boiling points for the following compounds is: (I)C2H5 OH (II)C2H5 Cl (III)C2H5 CH3 (IV) C2H5 OCH3 (1) (IV) < (III) < (I) < (II) (2) (III) < (II) < (I) < (IV) (3) (III) < (IV) < (II) < (I) (4) (II) < (III) < (IV) < (I) JEE Main 2017 (09 Apr Online) JEE Main Previous Year Paper

Q36.Among the following compounds, the compound which shows the highest dipole-moment is (1) (II) (2) (IV) (3) (III) (4) (I)

Q36.The enthalpy change on freezing of 1 mol of water at 5°C to ice at −5°C is: (Given Δfus H = 6 kJ mol−1 at 0°C, Cp(H2O, l) = 75 .3 J mol−1 K−1 Cp(H2O, s) = 36 .8 J mol−1 K−1 ) (1) 6 .00 kJ mol−1 (2) 5 .81 kJ mol−1 (3) 5 .44 kJ mol−1 (4) 6 .56 kJ mol−1

Q36.Given: Cgraphite + O2g →CO2g ; ΔrHo = −393 .5 kJ mol−1 1 H2g + 2O2g →H2Ol; ΔrHo = - 285 .8 kJ mol-1 CO2g + 2H2Ol →CH4g + 2O2g; ΔrHo = + 890 .3 kJ mol-1 Based on the above thermochemical equations, the value of ΔrHo at 298 K for the reaction Cgraphite + 2H2g →CH4g will be: (1) +144 .0 kJ mol-1 (2) -74 .8 kJ mol-1 (3) -144 .0 kJ mol-1 (4) +74 .8 kJ mol-1 Q37.ΔU is equal to: (1) Isobaric work (2) Adiabatic work (3) Isothermal work (4) Isochoric work

Q37.For a reaction, A(g) →A(l); ΔH = −3 RT. The correct statement for the reaction is (1) ΔH = ΔU = O (2) |ΔH| < |ΔU| (3) |ΔH| > |ΔU| (4) ΔH = ΔU ≠O

Q37.At 300 K, the density of a certain gaseous molecule at 2 bar is double to that of dinitrogen (N2) at 4 bar. The molar mass of the gaseous molecule is (1) 224 g mol−1 (2) 112 g mol−1 (3) 56 g mol−1 (4) 28 g mol−1

Q38.Addition of sodium hydroxide solution to a weak acid (HA) results in a buffer of pH 6. If ionization constant of HA is 10−5 , the ratio of salt to acid concentration in the buffer solution will be: (1) 10 : 1 (2) 4 : 5 (3) 5 : 4 (4) 1 : 10

Q38.pKa of a weak acid HA and pKb of a weak base BOH are 3.2 and 3.4 respectively. The pH of their salt AB solution at 25oC is (1) 6.9 (2) 7.0 (3) 1.0 (4) 7.2