Practice Questions

Q27.The ratio (R) of output resistance r0, and the input resistance ri in measurements of input and output characteristics of a transistor is typically in the range : JEE Main 2016 (10 Apr Online) JEE Main Previous Year Paper (1) R~102 −103 (2) R~1 −10 (3) R~0.1 −1.0 (4) R~0.1 −0.01

Q27.The temperature dependence of resistance of Cu and undoped Si in the temperature range 300 −400 K is best described by JEE Main 2016 (03 Apr) JEE Main Previous Year Paper (1) linear increase for Cu, exponential decrease for (2) linear decrease for Cu, linear decrease for Si Si (3) linear increase for Cu, linear increase for Si (4) linear increase for Cu, exponential increase for Si

Q27.An unknown transistor needs to be identified as a npn or pnp type. A multimeter, with +ve and -ve terminals, is used to measure resistance between different terminals of transistor. If terminal 2 is the base of the transistor then which of the following is correct for a pnp transistor? (1) +ve terminal 2, -ve terminal 3, resistance low (2) +ve terminal 2, -ve terminal 1, resistance high (3) +ve terminal 1, -ve terminal 2, resistance high (4) +ve terminal 3, -ve terminal 2, resistance high

Q28.A Zener diode with a breakdown voltage of 4 V is connected in series with a resistance R to a battery of emf 10 V . The maximum power dissipation rating for the Zener diode is 1 W. The value of R to ensure maximum power dissipation across the diode is (1) 12 Ω (2) 24 Ω (3) 36 Ω (4) 6 Ω

Q28.Identify the semiconductor devices whose characteristics are given below, in the order (a), (b), (c), (d): (1) Solar cell, Light dependent resistance, Zener (2) Zener diode, Solar cell, Simple diode, Light diode, Simple diode dependent resistance (3) Simple diode, Zener diode, Solar cell, Light (4) Zener diode, Simple diode, Light dependent dependent resistance resistance, Solar cell

Q28.To get an output of 1 from the circuit shown in the figure the input must be: (1) a = 0, b = 0, c = 1 (2) a = 1, b = 0, c = 0 (3) a = 1, b = 0, c = 1 (4) a = 0, b = 1, c = 0

Q29.A realistic graph depicting the variation of the reciprocal of input resistance in an input characteristics measurement in a common emitter transistor configuration is : (1) (2) (3) (4)

Q29.Choose the correct statement: (1) In frequency modulation the amplitude of the (2) In frequency modulation the amplitude of the high frequency carrier wave is made to vary in high frequency carrier wave is made to vary in proportion to the amplitude of the audio signal. proportion to the frequency of the audio signal. (3) In amplitude modulation the amplitude of the (4) In amplitude modulation the frequency of the high frequency carrier wave is made to vary in high frequency carrier wave is made to vary in proportion to the amplitude of the audio signal. proportion to the amplitude of the audio signal.

Q29.The truth table given in fig. represents: A B Y 0 0 0 0 1 1 1 0 1 1 1 1 (1) OR-Gate (2) NAND-Gate (3) AND-Gate (4) NOR-Gate

Q30.A modulated signal Cm(t) has the form Cm(t) = 30 sin 300πt + 10(cos 200πt −cos 400πt). The carrier frequency f ′c the modulating frequency(message frequency) fω and the modulation index μ are respectively given by : (1) fc = 200 Hz; fm = 50 Hz ; μ = 21 (2) fc = 150 Hz; fm = 50 Hz ; μ = 32 (3) fc = 150 Hz; fm = 30 Hz ; μ = 13 (4) fc = 200 Hz; fm = 30 Hz ; μ = 21

Q30.An audio signal consists of two distinct sounds: one a human speech signal in the frequency band of 200 Hz to 2700 Hz, while the other is a high frequency music signal in the frequency band of 10200 Hz to 15200 Hz. The ratio of the AM signal band width required to send both the signals together to the AM signal band width required to send just the human speech is: JEE Main 2016 (09 Apr Online) JEE Main Previous Year Paper (1) 3 (2) 5 (3) 6 (4) 2

Q30.A screw gauge with a pitch of 0.5 mm and a circular scale with 50 divisions is used to measure the thickness of a thin sheet of aluminium. Before starting the measurement, it is found that when the two jaws of the screw gauge are brought in contact, the 45th division coincides with the main scale line and that the zero of the main scale is barely visible. What is the thickness of the sheet if the main scale reading is 0 .5 mm and the 25th division coincides with the main scale line? (1) 0.70 mm (2) 0.50 mm (3) 0.75 mm (4) 0.80 mm JEE Main 2016 (03 Apr) JEE Main Previous Year Paper

Q31.Aqueous solution of which of the following salts will not contain ions with the electronic configuration 1s22s22p63s23p6 ? (1) NaF (2) KBr (3) NaCl (4) CaI2

Q31.An organic compound contains C, H and S. The minimum molecular weight of the compound containing 8% Sulphur is (1) 600 g mol−1 (2) 200 g mol−1 (3) 400 g mol−1 (4) 300 g mol−1

Q31.At 300 K and 1 atm, 15 mL of a gaseous hydrocarbon requires 375 mL air containing 20% O2 by volume, for complete combustion. After combustion, the gases occupy 345 mL. Assuming that the water formed is in liquid form and the volumes were measured at the same temperature and pressure, the formula of the hydrocarbon is: (Assume complete combustion of reactant) (1) C4H8 (2) C4H10 (3) C3H6 (4) C3H8

Q32.The following statements concern elements in the periodic table. Which of the following is true? (1) For group 15 elements, the stability of +5 (2) Elements of group 16 have lower ionization oxidation state increases down the group. enthalpy values compared to those of group 15 in the corresponding periods. (3) The group 13 elements are all metals. (4) All the elements in group 17 are gases.

Q32.A stream of electrons from a heat filament was passed between two charge plates kept at a potential difference V esu. If e and m are charge and mass of an electron, respectively, then the value of hλ (where λ is wavelength associated with the electron wave) is given by: (1) √meV (2) √2 meV (3) me V (4) 2 me V

Q32.The amount of arsenic pentasulphide that can be obtained when 35. 5 g arsenic acid is treated with excess H2S in the presence of conc. HCl (assuming 100% conversion) is (1) 0. 25 mol (2) 0. 50 mol (3) 0. 333 mol (4) 0. 125 mol

Q33.The total number of orbitals associated with the principal quantum number 5 is: (1) 20 (2) 25 (3) 10 (4) 5

Q33.Which of the following atoms has the highest first ionization energy? (1) K (2) Sc (3) Rb (4) Na

Q33.The bond angle H-X-H is the greatest in the compound : JEE Main 2016 (10 Apr Online) JEE Main Previous Year Paper (1) PH3 (2) CH4 (3) NH3 (4) H2O

Q34.Initially, the root-mean-square (RMS) velocity of N2 molecules at certain temperature is u. If this temperature is doubled and all the nitrogen molecules dissociate into nitrogen atoms, then the new RMS velocity will be: (1) 2 u (2) 14 u (3) 4 u (4) u/2

Q34.The species in which the N atom is a state of sp hybridization is: (1) NO−3 (2) NO2 (3) NO+2 (4) NO−2

Q34.The group of molecules having identical shape is: (1) PCl5, IF5, XeO2F2 (2) BF3, PCl3, XeO3 (3) SF4, XeF4, CCl4 (4) ClF3, XeOF2, XeF+3

Q35.At very high pressures, the compressibility factor of one mole of a gas is given by: (1) 1 + RTPb (2) RTPb (3) 1 −PbRT (4) 1 − (VRT)b