Practice Questions

Q22.In an optics experiment, with the position of the object fixed, a student varies the position of a convex lens and for each position, the screen is adjusted to get a clear image of the object. A graph between the object distance u and the image distance v, from the lens, is plotted using the same scale for the two axes. A straight line passing through the origin and making an angle of 45∘ with the x-axis meets the experimental curve at P . The coordinates of P will be (1) (2f, 2f) (2) ( f2 , f2 ) (3) (f, f) (4) (4f, 4f)

Q23.A transparent solid cylindrical rod has a refractive index of 2 . It is surrounded by air. A light ray is incident √3 at the mid point of one end of the rod as shown in the figure. The incident angle θ for which the light ray grazes along the wall of the rod is (1) sin−1 ( 21 ) (2) sin−1 ( √32 ) (3) sin−1 ( √32 ) (4) sin−1 ( √31 )

Q24.A mixture of light, consisting of wavelength 590 nm and an unknown wavelength, illuminates Young's double slit and gives rise to two overlapping interference patterns on the screen. The central maximum of both lights coincide. Further, it is observed that the third bright fringe of known light coincides with the 4th bright fringe of the unknown light. From this data, the wavelength of the unknown light is (1) 393.4 nm (2) 885.0 nm (3) 442.5 nm (4) 776.8 nm

Q25.The surface of a metal is illuminated with the light of 400 nm. The kinetic energy of the ejected photoelectrons was found to be 1.68eV. The work function of the metal is (hc = 1240eVnm) (1) 3.09eV (2) 1.41eV (3) 151eV (4) 1.68eV

Q26.The transition from the state n = 4 to n = 3 in a hydrogen like atom results in ultraviolet radiation. Infrared radiation will be obtained in the transition from (1) 2 →1 (2) 3 →2 (3) 4 →2 (4) 5 →4

Q27.The above is a plot of binding energy per nucleon Eb , against the nuclear mass M; A, B, C, D, E, F correspond to different nuclei. Consider four reactions: (i) A + B →C + ε (ii) C →A + B + ε (iii) D + E →F + ε and (iv) F →D + E + ε where ε is the energy released? In which reactions is ε positive? (1) (i) and (iv) (2) (i) and (iii) (3) (ii) and (iv) (4) (ii) and (iii) JEE Main 2009 JEE Main Previous Year Paper

Q28.A p-n junction (D) shown in the figure can act as a rectifier. An alternating current source (V ) is connected in the circuit. (1) (2) (3) (4)

Q29.The logic circuit shown below has the input waveforms 'A' and 'B' as shown. Pick out the correct output waveform. (1) (2) (3) (4)

Q30.In an experiment the angles are required to be measured using an instrument. 29 divisions of the main scale exactly coincide with the 30 divisions of the vernier scale. If the smallest division of the main scale is half-a- degree (= 0.5∘), then the least count of the instrument is (1) one minute (2) half minute (3) one degree (4) half degree

Q31.In an atom, an electron is moving with a speed of 600 m/s with an accuracy of 0.005%. Certainity with which the position of the electron can be located is (h = 6.6 × 10−34 kg m2 s−1 , mass of electron, em = 9.1 × 10−31 kg ) (1) 1.52 × 10−4 m (2) 5.10 × 10−3 m (3) 1.92 × 10−3 m (4) 3.84 × 10−3 m

Q32.Calculate the wavelength (in nanometer) associated with a proton moving at 1.0 × 103 ms−1 (Mass of proton = 1.67 × 10−27 kg and h = 6.63 × 10−34Js ): JEE Main 2009 JEE Main Previous Year Paper (1) 0.032 nm (2) 0.40 nm (3) 2.5 nm (4) 14.0 nm

Q33.In which of the following arrangements, the sequence is not strictly according to the property written against it ? (1) CO2 < SiO2 < SnO2 < PbO2 : increasing (2) HF < HCl < HBr < HI : increasing acid oxidising power strength (3) NH3 < PH3 < AsH3 < SbH3 : increasing basic (4) B < C < O < N : increasing first ionization strength enthalpy.

Q34.The set representing the correct order of ionic radius is : (1) Li+ > Be2+ > Na+ > Mg2+ (2) Na+ > Li+ > Mg2+ > Be2+ (3) Li+ > Na+ > Mg2+ > Be2+ (4) Mg2+ > Be2+ > Li+ > Na+

Q35.Using MO theory predict which of the following species has the shortest bond length ? (1) O2+2 (2) O+2 (3) O−2 (4) O2−2 =

Q36.On the basis of the following thermochemical data: (ΔfG∘H+(aq) 0) H2O(ℓ) →H+(aq) + OH−(aq); ΔH = 57.32 kJ 1 H2( g) + O2( g) →H2O(ℓ); ΔH = −286.20 kJ 2 The value of enthalpy of formation of OH− ion at 25∘C is: (1) −22.88 kJ (2) −228.88 kJ (3) +228.88 kJ (4) −343.52 kJ

Q37.Solid Ba (NO3)2 is gradually dissolved in a 1.0 × 10−4MNa2CO3 solution. At what concentration of Ba2+ will a precipitate begin to form ? (Ksp for BaCO3 = 5.1 × 10−9). (1) 4.1 × 10−5M (2) 5.1 × 10−5M (3) 8.1 × 10−8M (4) 8.1 × 10−7M

Q38.The bond dissociation energy of B −F in BF3 is 646 kJ mol −1 whereas that of C −F in CF4 is 515 kJ mol −1 . The correct reason for higher B-F bond dissociation energy as compared to that of C - F is : (1) smaller size of B-atom as compared to that of C- (2) stronger σ bond between B and F in BF3 as atom compared to that between C and F in CF4 (3) significant pπ −pπ interaction between B and F (4) lower degree of pπ −pπ interaction between B in BF3 whereas there is no possibility of such and F in BF3 than that between C and F in CF4 . interaction between C and F in CF4 . –––

Q39.Arrange the carbanions, (CH3)3C, CCl3, (CH3)2CH, C6H5CH2 , in order of their decreasing stability : –––––––– (1) C8H5CH2 > CCl3 > (CH3)3C > (CH3)2CH (2) (CH3)2CH > CCl3 > C6H5CH2 > (CH3)3C –––––––– (3) CCl3 > C8H5CH2 > (CH3)2CH > (CH3)3C (4) (CH3)3C > (CH3)2CH > C6H5CH2 > CCl3

Q40.The alkene that exhibits geometrical isomerism is: (1) propene (2) 2-methyl propene (3) 2-butene (4) 2- methyl -2- butene JEE Main 2009 JEE Main Previous Year Paper

Q41.The number of stereoisomers possible for a compound of the molecular formula CH3 −CH = CH −CH(OH) −Me is : (1) 3 (2) 2 (3) 4 (4) 6

Q42.The IUPAC name of neopentane is (1) 2-methylbutane (2) 2, 2-dimethylpropane (3) 2-methylpropane (4) 2,2-dimethylbutane

Q43.Copper crystallizes in fcc with a unit cell length of 361pm. What is the radius of copper atom ? (1) 108pm (2) 127pm (3) 157 pm (4) 181pm

Q44.Two liquids X and Y form an ideal solution. At 300 K, vapour pressure of the solution containing 1 mol of X and 3 mol of Y is 550 mmHg. At the same temperature, if 1 mol of Y is further added to this solution, vapour pressure of the solution increases by 10 mmHg . Vapour pressure (in mmHg ) of X and Y in their pure states will be, respectively : (1) 200 and 300 (2) 300 and 400 (3) 400 and 600 (4) 500 and 600

Q45.A binary liquid solution is prepared by mixing n-heptane and ethanol. Which one of the following statements is correct regarding the behaviour of the solution? (1) The solution formed is an ideal solution (2) The solution is non-ideal, showing +ve deviation from Raoult's law. (3) The solution is non-ideal, showing -ve deviation (4) n-heptane shows +ve deviation while ethanol from Raoult's law. shows -ve deviation from Raoult's law.

Q46.In a fuel cell methanol is used as fuel and oxygen gas is used as an oxidizer. The reaction is CH3OH(ℓ) + 23 O2( g) →CO2( g) + 2H2O(ℓ) At 298 K standard Gibb's energies of formation for CH3OH(ℓ), H2O(ℓ) and CO2( g) are −166.2, −237.2 and −394.4 kJ mol−1 respectively. If standard enthalpy of combustion of methanol is −726 kJ mol−1 , efficiency of the fuel cell will be (1) 80% (2) 87% (3) 90% (4) 97%