Practice Questions

Q63.A fish looking up through the water sees the outside world contained in a circular horizon. If the refractive index of water is 4/3 and the fish is 12 cm below the surface, the radius of this circle in cm is (1) 36√7 (2) 36/√7 (3) 36√5 (4) 4√5

Q64.A thin glass (refractive index 1.5) lens has optical power of −5D in air. Its optical power in a liquid medium with refractive index 1.6 will be (1) 1D (2) −1D (3) 25D (4) None of these

Q65.A Young’s double slit experiment uses a monochromatic source. The shape of the interference fringes formed on a screen is (1) hyperbola (2) circle (3) straight line (4) parabola JEE Main 2005 JEE Main Previous Year Paper

Q66.Two point white dots are 1 mm apart on a black paper. They are viewed by eye of pupil diameter 3 mm . Approximately, what is the maximum distance at which these dots can be resolved by the eye? [ Take wavelength of light = 500 nm ] (1) 5 m (2) 1 m (3) 6 m (4) 3 m

Q67.When an unpolarized light of intensity I0 is incident on a polarizing sheet, the intensity of the light which does not get transmitted is (1) 1 2 I0 (2) 41 I0 (3) zero (4) I0

Q68.If I0 is the intensity of the principal maximum in the single slit diffraction pattern, then what will be its intensity when the slit width is doubled? (1) 2I0 (2) 4I0 (3) I0 (4) I0/2

Q69.A photocell is illuminated by a small bright source placed 1 m away. When the same source of light is placed 1 m away, the number of electrons emitted by photo cathode would 2 (1) decrease by a factor of 4 (2) increase by a factor of 4 (3) decrease by a factor of 2 (4) increase by a factor of 2

Q70.If the kinetic energy of a free electron doubles. Its deBroglie wavelength changes by the factor (1) 1 (2) 2 2 (3) 1 (4) √2 √2

Q71.The diagram shows the energy levels for an electron in a certain atom. Which transition shown represents the emission of a photon with the most energy ? (1) III (2) IV (3) I (4) II

Q72.The intensity of gamma radiation from a given source is I. On passing through 36 mm of lead, it is reduced to I . The thickness of lead which will reduce the intensity to I will be 8 2 (1) 6 mm (2) 9 mm (3) 18 mm (4) 12 mm

Q73.Starting with a sample of pure 66Cu, 7/8 of it decays into Zn in 15 minutes. The corresponding half-life is (1) 10 minutes (2) 15 minutes (3) 5 minutes (4) 7 12 minutes

Q74.If radius of 2713Al nucleus is estimated to be 3.6 Fermi then the radius 12552 Te nucleus be nearly JEE Main 2005 JEE Main Previous Year Paper (1) 6 fermi (2) 8 fermi (3) 4 fermi (4) 5 fermi

Q75.A nuclear transformation is denoted by X(n, α)73Li. Which of the following is the nucleus of element X ? (1) 12C6 (2) 105 B (3) 95 B (4) 114 Be

Q76.The electrical conductivity of a semiconductor increases when electromagnetic radiation of wavelength shorter than 2480 nm is incident on it. The band gap in (eV) for the semiconductor is (1) 1.1eV (2) 2.5eV (3) 0.5eV (4) 0.7eV

Q77.In a common base amplifier, the phase difference between the input signal voltage and output voltage is (1) π (2) π 4 (3) 0 (4) π2

Q78.In a full wave rectifier circuit operating from 50 Hz mains frequency, the fundamental frequency in the ripple would be (1) 50 Hz (2) 25 Hz (3) 100 Hz (4) 70.7 Hz

Q79.Two solutions of a substance (non electrolyte) are mixed in the following manner. 480 ml of 1.5 M first solution + 520 mL of 1.2 M second solution. What is the molarity of the final mixture? (1) 1.20 M (2) 1.50 M (3) 1.344 M (4) 2.70 M

Q80.If we consider that 1 , in place of 1 ; mass of carbon atom is taken to be the relative atomic mass unit, the 6 12 mass of one mole of a substance will (1) Decrease twice (2) Increase two fold (3) Remain unchanged (4) Be a function of the molecular mass of the substance

Q81.An organic compound having molecular mass 60 is found to contain C = 20%, H = 6.67% and N = 46.67% while rest is oxygen. On heating it gives NH3 alongwith a solid residue. The solid residue give violet colour with alkaline copper sulphate solution. The compound is (1) CH3NCO (2) CH3CONH2 (3) (NH2)2CO (4) CH3CH2CONH2

Q82.In a multi – electron atom, which of the following orbitals described by the three quantum numbers will have the same energy in the absence of magnetic acid and electric fields? (a) n = 1, l = 0, m = 0 (b) n = 2, l = 0, m = 0 (c) n = 2, l = 1, m = 1 (d) n = 3, l = 2, m = 1 (e) n = 3, l = 2, m = 0 (1) (a) and (b) (2) (b) and (c) (3) (c) and (d) (4) (d) and (e)

Q83.Of the following sets which one does NOT contain isoelectronic species? JEE Main 2005 JEE Main Previous Year Paper (1) (2) CN, N2, C22 PO−34 , SO−24 , ClO−4 (3) SO−23 , CO−23 , NO−3 (4) BO−33 , CO−23 , NO3

Q84.Which of the following statements in relation to the hydrogen atom is correct? (1) 3s orbital is lower in energy than 3p orbital (2) 3p orbital is lower in energy than 3d orbital (3) 3s and 3p orbitals are of lower energy than 3d (4) 3s, 3p and 3d orbitals all have the same energy orbital

Q85.In which of the following arrangements the order is NOT according to the property indicated against it? (1) (2) Al3+ < Mg2+ < Na+ < F− B < C < N < O Increasing first ionization enthalpy Increasing ionic size (3) (4) Li < Na < K < Rb Increasing metallic radius l < Br < F < Cl Increasing electron gain enthalpy (with negative sign)

Q86.The photon of hard gamma radiation knocks a proton out of 2412Mg nucleus to form (1) the isotope of parent nucleus (2) the isobar of parent nucleus (3) the nuclide 2311Na (4) the isobar of 2311Na

Q87.Which of the following oxides is amphoteric in character? (1) CaO (2) CO2 (3) SiO2 (4) SnO2