Practice Questions

Q28.A current I flows along the length of an infinitely long, straight, thin walled pipe. Then JEE Main 2007 JEE Main Previous Year Paper (1) the magnetic field is zero only on the axis of the (2) the magnetic field is different at different points pipe inside the pipe (3) the magnetic field at any point inside the pipe is (4) the magnetic field at all points inside the pipe is zero the same, but not zero

Q30.A charged particle moves through a magnetic field perpendicular to its direction. Then (1) the momentum changes but the kinetic energy is (2) both momentum and kinetic energy of the constant particle are not constant (3) both, momentum and kinetic energy of the (4) kinetic energy changes but the momentum is particle are constant constant

Q33.In an a.c. circuit the voltage applied is E = E0 sin ωt. The resulting current in the circuit is I = I0 sin (ωt −π2 ). The power consumption in the circuit is given by (1) P = E0I0 (2) P = zero √2 (3) P = E0I02 (4) P√2E0I0

Q34.Two lenses of power −15 D and +5 D are in contact with each other. The focal length of the combination is (1) −20 cm (2) −10 cm (3) +20 cm (4) +10 cm

Q36.Photon of frequency v has a momentum associated with it. If c is the velocity of light, the momentum is JEE Main 2007 JEE Main Previous Year Paper (1) v/c (2) hvc (3) hv/c2 (4) hv/c

Q37.Which of the following transitions in hydrogen atoms emit photons of highest frequency? (1) n = 2 to n = 6 (2) n = 6 to n = 2 (3) n = 2 to n = 1 (4) n = 1 to n = 2

Q39.In gamma ray emission from a nucleus (1) both the neutron number and the proton number (2) there is no change in the proton number and the change neutron number. (3) only the neutron number changes (4) only the proton number changes

Q1. Which of the following units denotes the dimensions ML2/Q2 , where Q denotes the electric charge? (1) Weber (Wb) (2) Wb/m2 (3) Henry (H) (4) H/m2

Q5. A player caught a cricket ball of mass 150 g moving at a rate of 20 m/s. If the catching process is completed in 0.1 s, the force of the blow exerted by the ball on the hand of the player is equal to (1) 300 N (2) 150 N (3) 3 N (4) 30 N

Q9. A bomb of mass 16 kg at rest explodes into two pieces of masses of 4 kg and 12 kg. The velocity of the 12 kg mass is 4 ms−1 . The kinetic energy of the other mass is JEE Main 2006 JEE Main Previous Year Paper (1) 96 J (2) 144 J (3) 288 J (4) 192 J

Q20.The maximum velocity of a particle, executing simple harmonic motion with an amplitude 7 mm, is 4.4 m/s. The period of oscillation is (1) 100 s (2) 0.01 s (3) 10 s (4) 0.1 s

Q28.The Kirchhoff's first law (∑i = 0) and second law (∑iR = ∑E), where the symbols have their usual meanings, are respectively based on (1) conservation of charge, conservation of energy (2) conservation of charge, conservation of momentum (3) conservation of energy, conservation of charge (4) conservation of momentum, conservation of charge

Q32.A thermocouple is made from two metals, Antimony and Bismuth. If one junction of the couple is kept hot and the other is kept cold then, an electric current will (1) flow from Antimony to Bismuth at the cold (2) flow from Antimony to Bismuth at the hot junction junction (3) flow from Bismuth to Antimony at the cold (4) not flow through the thermocouple junction

Q34.Needles N1, N2 and N3 are made of a ferromagnetic, a paramagnetic and a diamagnetic substance respectively. A magnet when brought close to them will (1) attract all three of them (2) attract N1 and N2 strongly but repel N3 (3) attract N1 strongly, N2 weakly and repel N3 (4) attract N1 strongly, but repel N2 and N3 weakly weakly

Q37.In an AC generator, a coil with N turns, all of the same area A and total resistance R, rotates with frequency ω in a magnetic field B. The maximum value of emf generated in the coil is " (1) N.A.B. ω (2) N.A.B.R. ω (3) N.A.B (4) N.A.B.R

Q38.The flux linked with a coil at any instant ' t ' is given by ϕ = 10t2 −50t + 250 The induced emf at t = 3 s is (1) 190 V (2) −190 V (3) −10 V (4) 10 V

Q42.The refractive index of glass is 1.520 for red light and 1.525 for blue light. Let D1 and D2 be an of minimum deviation for red and blue light respectively in a prism of this glass. Then (1) D1 > D2 (2) D1 < D2 (3) D1 = D2 (4) D1 can be less than or greater than depending upon the angle of prism

Q43.The time by a photoelectron to come out after the photon strikes is approximately (1) 10−1 s (2) 10−4 s (3) 10−10 s (4) 10−16 s

Q47.The energy spectrum of β-particles [number N(E) as a function of β-energy E ] emitted from a radioactive source is (1) (2) (3) (4)

Q50.The 'rad' is the correct unit used to report the measurement of (1) the rate of decay of radioactive source (2) the ability of a beam of gamma ray photons to produce ions in a target (3) the energy delivered by radiation to a target. (4) the biological effect of radiation

Q53.In a common base mode of a transistor, t collector current is 5.488 mA for an emit current of 5.60 mA. The value of the base current amplification factor (β) will be (1) 48 (2) 49 (3) 50 (4) 51

Q55.In the following, which one of the diodes is reverse biased? JEE Main 2006 JEE Main Previous Year Paper (1) (2) (3) (4)

Q2. Out of the following pair, which one does NOT have identical dimensions is (1) angular momentum and Planck's constant (2) impulse and momentum (3) moment of inertia and moment of a force (4) work and torque

Q13.A particle of mass 0.3 kg is subjected to a force F = −kx with k = 15 N/m. What will be its initial acceleration if it is released from a point 20 cm away from the origin? (1) 3 m/s2 (2) 15 m/s2 (3) 5 m/s2 (4) 10 m/s2

Q17.A spherical ball of mass 20 kg is stationary at the top of a hill of height 100 m. It rolls down a smooth surface to the ground, then climbs up another hill of height 30 m and finally rolls down to a horizontal base at a height of 20 m above the ground. The velocity attained by the ball is JEE Main 2005 JEE Main Previous Year Paper (1) 40 m/s (2) 20 m/s (3) 10 m/s (4) 10√30 m/s