Practice Questions

Q12.Two particles are performing simple harmonic motion in a straight line about the same equilibrium point. The amplitude and time period for both particles are same and equal to A and T , respectively. At time t = 0 one particle has displacement A while the other one has displacement −A2 and they are moving towards each other. If they cross each other at time t, then t is: (1) 5T (2) T 6 3 (3) T (4) T 4 6

Q15.A galvanometer having a coil resistance of 100 Ω gives a full scale deflection, when a current of 1 mA is passed through it. The value of the resistance, which can convert this galvanometer into ammeter giving a full scale deflection for a current of 10 A, is: (1) 0.1 Ω (2) 3 Ω (3) 0.01 Ω (4) 2 Ω JEE Main 2016 (03 Apr) JEE Main Previous Year Paper

Q16. In the circuit shown, the resistance r is a variable resistance. If for r = fR , the heat generation in r is maximum then the value of f is (1) 1 (2) 1 2 (3) 1 (4) 3 4 4

Q19.Arrange the following electromagnetic radiations per quantum in the order of increasing energy: A : Blue light B : Yellow light C : X-ray D : Radiowave (1) C, A, B, D (2) B, A, D, C (3) D, B, A, C (4) A, B, D, C

Q20.A series LR circuit is connected to a voltage source with V (t) = V0 sin(ωt) . After a very large time, current I(t) behaves as (t0 ≫LR ): JEE Main 2016 (09 Apr Online) JEE Main Previous Year Paper (1) (2) (3) (4)

Q20.An observer looks at a distant tree of height 10 m with a telescope of magnifying power of 20. To the observer, the tree appears as (1) 20 times taller. (2) 20 times nearer. (3) 10 times taller. (4) 10 times nearer. JEE Main 2016 (03 Apr) JEE Main Previous Year Paper

Q21.Microwave oven acts on the principle of: (1) giving rotational energy to water molecules (2) giving translational energy to water molecules (3) giving vibrational energy to water molecules (4) transferring electrons from lower to higher energy levels in water molecule

Q22.To determine refractive index of glass slab using a travelling microscope, minimum number of readings required are : (1) Two (2) Four (3) Three (4) Five

Q25.For a common emitter configuration, if α and β have their usual meanings, the correct relationship between α and β is: β β2 (1) α = 1+β (2) α = 1+β2 (3) α 1 = β1 −1 (4) α = 1−ββ

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

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

Q4. If a body moving in a circular path maintains constant speed of 10 m s−1 , then which of the following correctly describes the relation between acceleration and radius? (1) (2) (3) (4)

Q4. Distance of the centre of mass of a solid uniform cone from its vertex is z0 . If the radius of its base is R and its height is h then z0 is equal to: JEE Main 2015 (04 Apr) JEE Main Previous Year Paper (1) 3h2 (2) h2 8R 4R (3) 3h (4) 5h 4 8

Q4. From the top of a 64 metres high tower, a stone is thrown upwards vertically with the velocity of 48 m/s. The greatest height (in metres) attained by the stone, assuming the value of the gravitational acceleration g = 32 m/s2 , is: (1) 112 (2) 88 (3) 128 (4) 100

Q10.An experiment takes 10 min to raise the temperature of water in a container from 0oC to 100oC and another 55 min to convert it totally into steam by a heater supplying heat at a uniform rate. Neglecting the specific heat of the container and taking specific heat of the water to be 1 cal (g∘C)−1 , the heat of vaporization according to this experiment will come out to be: (1) 530 cal g−1 (2) 550 cal g−1 (3) 540 cal g−1 (4) 560 cal g−1

Q17.In the given circuits (a) and (b), switches S1 and S2 are closed at t = 0 and kept close for a long time. The variation of currents in the two circuits for t ≥0 are shown in the options. (Figures are schematic and not drawn to scale.) JEE Main 2015 (10 Apr Online) JEE Main Previous Year Paper (1) (2) (3) (4)

Q21.Two long straight parallel wires, carrying (adjustable) currents I1 and I2 , are kept at a distance d apart. If the force F between the two wires is taken as 'positive' when the wires repel each other and 'negative' when the wires attract each other, the graph showing the dependence of F , on the product I1I2 , would be: (1) (2) (3) (4)

Q22.The AC voltage across a resistance can be measured using a: (1) Moving magnet galvanometer (2) Moving coil galvanometer (3) Hot wire voltmeter (4) Potentiometer

Q22.When the current in a coil changes from 5 A to 2 A in 0.1 s, an average voltage of 50 V is produced. The self- inductance of the coil is (1) 1.67 H (2) 6 H (3) 3 H (4) 0.67 H

Q27.De-Broglie wavelength of an electron accelerated by a voltage of 50 V is close to (|e| = 1.6 × 10−19 C, me = 9.1 × 10−31 kg, h = 6.6 × 10−34 J s) (1) 0.5 Å (2) 1.2 Å (3) 1.7 Å (4) 2.4 Å

Q28.Match list-I (Fundamental Experiment) with List-II (its conclusion) and select the correct option from the choices given below the list: List-I List-II A Franck-Hertz Experiment (i) Particle nature of light B Photo-electric experiment (ii) Discrete energy levels of the atom C Davison-Germer Experiment (iii) Wave nature of electron (iv) Structure of atom (1) A −(iv) ; B −(iii); C −(ii) (2) A −(i) ; B −(iv); C −(iii) (3) A −(ii) ; B −(iv); C −(iii) (4) A −(ii) ; B −(i); C −(iii)

Q29.In an unbiased p - n junction electrons diffuse from n-region to p-region because: (1) electrons travel across the junction due to (2) only electrons move from n to p region and not potential difference the vice - versa (3) electron concentration in n - region is more as (4) holes in p - region attract them compared to that in p - region

Q30.A signal of 5 kHz frequency is amplitude modulated on a carrier wave of frequency 2 MHz. The frequencies of the resultant signal is/are: JEE Main 2015 (04 Apr) JEE Main Previous Year Paper (1) 2000 kHz and 1995 kHz (2) 2 MHz only (3) 2005 kHz and 1995 kHz (4) 2005 kHz, 2000 kHz and 1995 kHz

Q2. A person climbs up a stalled escalator in 60 s. If standing on the same but escalator running with constant velocity he takes 40 s. How much time is taken by the person to walk up the moving escalator? (1) 37 s (2) 27 s (3) 24 s (4) 45 s