Practice Questions

Q64.A light ray is incident perpendicular to one face of a 90∘ prism and is totally internally reflected at the glass-air interface. If the angle of reflection is 45∘ , we conclude that the refractive index n (1) n < 12 (2) n > √2 (3) n > 1 (4) n < √2 √2

Q65.A plane convex lens of refractive index 1.5 and radius of curvature 30 cm is silvered at the curved surface. Now this lens has been used to form the image of an object. At what distance from this lens an object be placed in order to have a real image of the size of the object? (1) 20 cm (2) 30 cm (3) 60 cm (4) 80 cm

Q66.The angle of incidence at which reflected light totally polarized for reflection from air to glass (refractive index n ), is (1) sin−1(n) (2) sin−1(1/n) (3) tan−1(1/n) (4) tan−1(n)

Q67.The maximum number of possible interference maxima for slit-separation equal to twice the wavelength in Young's double-slit experiment is (1) infinite (2) five (3) three (4) zero

Q68.A radiation of energy E falls normally on a perfectly reflecting surface. The momentum transferred to the surface is (1) E/c (2) 2E/c (3) Ec (4) E/c2

Q69.According to EInstein's photoelectric equation, the plot of the kinetic energy of the emitted photo electrons from a metal Vs the frequency, of the incident radiation gives straight line whose slope JEE Main 2004 JEE Main Previous Year Paper (1) depends on the nature of the metal used (2) depends on the intensity of the radiation (3) depends both on the intensity of the radiation and (4) is the same for all metals and independent of the the metal used intensity of the radiation.

Q70.The work function of a substance is 4.0eV . Then longest wavelength of light that can cause photoelectron emission from this substance approximately (1) 540 nm (2) 400 nm (3) 310 nm (4) 220 nm

Q71.The manifestation of band structure in solids is due to (1) Heisenberg's uncertainty principle (2) Pauli's exclusion principle (3) Bohr's correspondence principle (4) Boltzmann's law

Q72.A nucleus disintegrates into two nuclear parts which have their velocities in the ratio 2 : 1. The ratio of their nuclear sizes will be (1) 21/3 : 1 (2) 1 : 31/2 (3) 31/2 : 1 (4) 1 : 21/3

Q73.The binding energy per nucleon of deuteron (21H) and helium nucleus (42He) is 1.1MeV and 7MeV respectively. If two deuteron nuclei react to form a single helium nucleus, then the energy released is (1) 13.9MeV (2) 26.9MeV (3) 23.6MeV (4) 19.2MeV

Q74.When npn transistor is used as amplifier (1) electrons move from base to collector (2) holes move from emitter to base (3) electrons move from collector to base (4) holes move from base to emitter.

Q75.For a transistor amplifier in common emitter configuration having load impedance of 1kΩ (hfe = 50 and hoe = 25 ) the current gain is (1) −5.2 (2) −15.7 (3) −24.8 (4) −48.78

Q76.When p-n junction diode is forward biased (1) the depletion region is reduced and barrier height (2) the depletion region is widened and barrier height is increased is reduced (3) both the depletion region and barrier height (4) both the depletion region and barrier height reduced increased. Q77. 6.02 × 1020 molecules of urea are present in 100ml of its solution. The concentration of urea solution is (1) 0.001M (2) 0.1M (3) 0.02M (4) 0.01M

Q78.To neutralize completely 20 mL of 0.1M aqueous solution of phosphorous acid (H3PO3), the volume of 0.1M aqueous KOH solution required is (1) 10 mL (2) 60 mL (3) 40 mL (4) 20 mL JEE Main 2004 JEE Main Previous Year Paper

Q79.Which of the following sets of quantum numbers is correct for an electron in 4f orbital? (1) n = 4, l = 3, m = +4, s = + 12 (2) n = 3, I = 2, m = −2, S = + 12 (3) n = 4, I = 3, m = +1, s = + 12 (4) n = 4, I = 4, m −4, s = −12

Q80.Consider the ground state of Cr atom (Z = 24). The number of electrons with the azimuthal quantum numbers I = 1 and 2 are respectively (1) 12 and 4 (2) 16 and 5 (3) 16 and 4 (4) 12 and 5

Q81.The wavelength of the radiation emitted, when in hydrogen atom electron falls from infinity to stationary state 1 , would be (Rydberg constant = 1.097 × 107 m−1) (1) 91 nm (2) 9.1 × 10−8 nm (3) 406 nm (4) 192 nm

Q82.Which one the following sets of ions represents the collection of isoelectronic species? (1) K+, Ca2+, Sc3+, Cl− (2) Na+, Mg2+, Al3+, Cl− (3) K+, Cl−, Mg2+, Sc3+ (4) Na+, Ca2+, Sc3+, F−

Q83.Which one the following ions has the highest value of ionic radius? (1) Li+ (2) F− (3) O2− (4) B3+

Q84.Consider the following nuclear reactions 238 92 M →xyN + 42He N y N →ABL + 2β+ The number of neutrons in the element L is (1) 142 (2) 146 (3) 140 (4) 144

Q85.The correct order of bond angles (smallest first) in H2 S, NH3, BF3 and SiH4 is (1) H2 S < SiH4 < NH3 < BF3 (2) H2 S < NH3 < BF3 < SiH4 (3) H2 S < NH3 < SiH4 < BF3 (4) NH3 < H2 S < SiH4 < BF3

Q86.The bond order in NO is 2.5 while that in NO+ is 3 . Which of the following statements is true for these two species? (1) Bond length in NO+ is greater than in NO (2) Bond length is unpredictable (3) Bond length in NO+ in equal to that in NO (4) Bond length in NO is greater than in NO+

Q87.The states of hybridization of boron and oxygen atoms in boric acid (H3BO3) are respectively (1) sp2 and sp2 (2) sp3 and sp3 (3) sp3 and sp2 (4) sp2 and sp3

Q88.Which one of the following has the regular tetrahedral structure? JEE Main 2004 JEE Main Previous Year Paper (1) XeF4 (2) [Ni(CN)4]2− (3) BF4−4 (4) SF4

Q89.The maximum number of 90∘ angles between bond pair of electrons is observed in (1) dsp 3 hybridization (2) sp3 d2 hybridization (3) dsp2 hybridization (4) sp3 d hybridization