Practice Questions

Q10.A 25 m long antenna is mounted on an antenna tower. The height of the antenna tower is 75 m . The wavelength (in meter) of the signal transmitted by this antenna would be : (1) 300 (2) 400 (3) 200 (4) 100

Q10.A particle starts executing simple harmonic motion (SHM) of amplitude a and total energy E. At any instant, its kinetic energy is 3E , then its displacement y is given by: 4 (1) y = a (2) y = a √2 (3) y = a√32 (4) y = a2

Q10.A cylindrical container of volume 4. 0 × 10−3 m3 contains one mole of hydrogen and two moles of carbon dioxide. Assume the temperature of the mixture is 400 K. The pressure of the mixture of gases is : [Take gas constant as 8. 3 J mol−1 K−1] (1) 24. 9 × 103 Pa (2) 249 × 101 Pa (3) 24. 9 × 105 Pa (4) 24. 9 Pa

Q10.Two particles A and B of equal masses are suspended from two massless springs of spring constants K1 and K2 respectively.If the maximum velocities during oscillations are equal, the ratio of the amplitude of A and B is (1) K2 (2) K1 K1 K2 (3) √K1K2 (4) √K2K1

Q10.A resistor develops 500 J of thermal energy in 20 s when a current of 1. 5 A is passed through it. If the current is increased from 1. 5 A to 3 A , what will be the energy developed in 20 s. (1) 1500 J (2) 1000 J (3) 500 J (4) 2000 J → → →

Q11.A particle executes S.H.M., the graph of velocity as a function of displacement is : (1) a circle (2) a helix (3) a parabola (4) an ellipse

Q11.Two ideal electric dipoles A and B, having their dipole moment p1 and p2 respectively are placed on a plane with their centres at O as shown in the figure. At point C on the axis of dipole A, the resultant electric field is making an angle of 37° with the axis. The ratio of the dipole moment of A and B, p1 is : ( take sin 37°= 53 ) p2 (1) 3 (2) 3 8 2 (3) 2 (4) 4 3 3

Q11.A charge Q is moving dl distance in the magnetic field B. Find the value of work done by B. (1) 1 (2) Infinite (3) Zero (4) −1 → x . A square loop of side d is placed with its edges along

Q11.For what value of displacement the kinetic energy and potential energy of a simple harmonic oscillation become equal? JEE Main 2021 (17 Mar Shift 1) JEE Main Previous Year Paper (1) x = 0 (2) x = ±A (3) x = ± A (4) x = A2 √2

Q12.For full scale deflection of total 50 divisions, 50 mV voltage is required in galvanometer. The resistance of galvanometer if its current sensitivity is 2 div / mA will be: (1) 1 Ω (2) 2 Ω (3) 5 Ω (4) 4 Ω

Q12.Match List I with List II. List I List II (a) Rectifier (i) Used either for stepping up or stepping down the A.C. voltage (b)Stabilizer (ii) Used to convert A.C. voltage into D.C. voltage (c) Transformer(iii)Used to remove any ripple in the rectified output voltage Used for constant output voltage even when the input voltage (d)Filter (iv) or load current change Choose the correct answer from the options given below: (1) (a) −(ii), (b) −(iv), (c) −(i), (d) −(iii) (2) (a) −(ii), (b) −(i), (c) −(iv), (d) −(iii) (3) (a) −(ii), (b) −(i), (c) −(iii), (d) −(iv) (4) (a) −(iii), (b) −(iv), (c) −(i), (d) −(ii)

Q12.The relative permittivity of distilled water is 81. The velocity of light in it will be: (Given μr = 1) (1) 4. 33 × 107 m s−1 (2) 2. 33 × 107 m s−1 (3) 3. 33 × 107 m s−1 (4) 5. 33 × 107 m s−1

Q12.The correct relation between the degrees of freedom f and the ratio of specific heat γ is: (1) f = γ−12 (2) f = γ+12 (3) f = γ+12 (4) f = γ+11

Q13.The colour coding on a carbon resistor is shown in the given figure. The resistance value of the given resistor is: (1) (7500 ± 375)Ω (2) (5700 ± 285)Ω (3) (7500 ± 755)Ω (4) (5700 ± 375)Ω

Q13.A plane electromagnetic wave of frequency 100 MHz is traveling in a vacuum along the x−direction. At a → → particular point in space and time, B = 2. 0 × 10−8 ˆkT⋅ (where, ˆk is unit vector along z−direction) What is E at this point? (1) 0. 6ˆj V m−1 (2) 6. 0ˆk V m−1 (3) 6. 0ˆj V m−1 (4) 0. 6ˆk V m−1

Q14.A current through a wire depends on time as 𝑖= 𝛼0𝑡+ 𝛽𝑡2, where 𝛼0 = 20 A s-1 and 𝛽= 8 A s-2. Find the charge crossed through a section of the wire in 15 s . (1) 2250 C (2) 11250 C (3) 2100 C (4) 260 C

Q14.The given potentiometer has its wire of resistance 10 Ω. When the sliding contact is in the middle of the potentiometer wire, the potential drop across 2 Ω resistor is: (1) 10 V (2) 5 V (3) 40 9 V (4) 4011 V

Q14.In a series LCR circuit, the inductive reactance (XL) is 10 Ω and the capacitive reactance (XC) is 4 Ω. The resistance (R) in the circuit is 6 Ω. The power factor of the circuit is : (1) 21 (2) 2√21 (3) 1 (4) √3 √2 2 JEE Main 2021 (18 Mar Shift 2) JEE Main Previous Year Paper

Q14.Following plots show Magnetization ( 𝑀) vs Magnetising field ( 𝐻) and Magnetic susceptibility ( χ ) vs Temperature ( 𝑇) graph : Which of the following combination will be represented by a diamagnetic material? (1) ( b ) , ( c ) (2) ( b ) , ( d ) (3) ( a ) , ( d ) (4) ( a ) , ( c )

Q14.In an ac circuit, an inductor, a capacitor and a resistor are connected in series with XL = R = XC. Impedance of this circuit is : (1) Zero (2) R (3) R√2 (4) 2R2 JEE Main 2021 (31 Aug Shift 1) JEE Main Previous Year Paper

Q14.The resistance of a conductor at 15°C is 16 Ω and at 100°C is 20 Ω. What will be the temperature coefficient of resistance of the conductor? (1) 0. 010°C−1 (2) 0. 033°C−1 (3) 0. 003°C−1 (4) 0. 042°C−1

Q15.A cell 𝐸1 of emf 6 V and internal resistance 2Ω is connected with another cell 𝐸2 of emf 4 V and internal resistance 8 Ω (as shown in the figure). The potential difference across points 𝑋 and 𝑌 is: (1) 10 . 0 V (2) 5 . 6 V (3) 2 . 0 V (4) 3 . 6 V

Q15.An electron of mass me and a proton of mass mp = 1836 me are moving with the same speed. The ratio of their de Broglie wavelength λelectron will be : λproton (1) 1836 (2) 18361 (3) 918 (4) 1

Q15.What should be the order of arrangement of de-Broglie wavelength of electron 𝜆e, an 𝛼-particle 𝜆α and proton 𝜆p given that all have the same kinetic energy ? (1) 𝜆𝑒= 𝜆𝑝= 𝜆𝛼 (2) 𝜆e < 𝜆p < 𝜆α (3) 𝜆e > 𝜆p > 𝜆α (4) 𝜆e = 𝜆p > 𝜆α

Q15.A coil is placed in a magnetic field →𝐵 as shown below : → A current is induced in the coil because 𝐵 is : (1) parallel to the plane of coil and increasing with (2) outward and increasing with time time (3) outward and decreasing with time (4) parallel to the plane of coil and decreasing with time + ^j cos𝑘𝑧- 𝜔𝑡 where ^i, ^j