Practice Questions

Q12.The charge flowing in a conductor changes with time as 𝑄𝑡= 𝛼𝑡- 𝛽𝑡2 + 𝛾𝑡3, where 𝛼, 𝛽 and 𝛾 are constants. Minimum value of current is: (1) 3𝛽2 (2) 𝛾2 𝛼- 𝛼- 𝛾 3𝛽 (3) 𝛽- 𝛼2 (4) 𝛼- 𝛽2 3𝛾 3𝛾

Q12.The equivalent resistance of the circuit shown below between points 𝑎 and 𝑏 is : JEE Main 2023 (10 Apr Shift 1) JEE Main Previous Year Paper (1) 16 Ω (2) 3 . 2 Ω (3) 24 Ω (4) 20 Ω

Q12.A hypothetical gas expands adiabatically such that its volume changes from 08 litres to 27 litres. If the ratio of final pressure of the gas to initial pressure of the gas is 16 . Then the ratio of Cp will be. 81 Cv (1) 4 (2) 3 3 1 (3) 21 (4) 32

Q12.A long straight wire of circular cross-section (radius 𝑎) is carrying steady current I . The current I is uniformly distributed across this cross-section. The magnetic field is (1) inversely proportional to 𝑟 in the region 𝑟< 𝑎 (2) directly proportional to 𝑟 in the region 𝑟< 𝑎 and and uniform throughout in the region 𝑟> 𝑎 inversely proportional to 𝑟 in the region 𝑟> 𝑎 (3) Zero in the region 𝑟< 𝑎 and inversely (4) uniform in the region 𝑟< 𝑎 and inversely proportional to 𝑟 in the region 𝑟> 𝑎 proportional to distance 𝑟 from the axis, in the region 𝑟> 𝑎

Q12.The equivalent resistance between 𝐴 𝑎𝑛𝑑 𝐵 of the network shown in figure: 2𝑅 (1) 11 (2) 14 𝑅 3 (3) 21 𝑅 (4) 8 𝑅 3

Q12.Heat energy of 184 kJ is given to ice of mass 600 g at −12 °C, Specific heat of ice is 2222. 3 J kg–1 °C–1 and latent heat of ice is 336 kJ kg–1 . (A) Final temperature of system will be 0 °C (B) Final temperature of the system will be greater than 0 °C (C) The final system will have a mixture of ice and water in the ratio of 5 : 1 (D) The final system will have a mixture of ice and water in the ratio of 1 : 5 (E) The final system will have water only Choose the correct answer from the options given below : JEE Main 2023 (29 Jan Shift 2) JEE Main Previous Year Paper (1) A and D only (2) B and D only (3) A and E only (4) A and C only times to that of its average speed in the gas. Then, the

Q12.In an Isothermal change, the change in pressure and volume of a gas can be represented for three different temperature; T3 > T2 > T1 as: JEE Main 2023 (24 Jan Shift 2) JEE Main Previous Year Paper (1) (2) (3) (4)

Q12.The rms speed of oxygen molecule in a vessel at particular temperature is (1 + x 1 speed of the molecule. The value of x will be: (take π = 227 ) (1) 27 (2) 8 (3) 28 (4) 4

Q12.An air bubble of diameter 6 mm rises steadily through a solution of density 1750 kg m−3 at the rate of 0. 35 cm s−1 . The co-efficient of viscosity of the solution (neglect density of air) is ________ Pas (given, g = 10 m s−2 ).

Q12.A bar magnet is released from rest along the axis of a very long vertical copper tube. After some time the magnet will (1) Move down with an acceleration equal to g (2) Oscillate inside the tube (3) Move down with almost constant speed (4) Move down with an acceleration greater than g

Q12.An engine operating between the boiling and freezing points of water will have A. Efficiency more than 27% . B. Efficiency less than the efficiency of a Carnot engine operating between the same two temperatures. C. Efficiency equal to 27% . D. Efficiency less than 27% . Choose the correct answer from the options given below (1) B, C and D only (2) A and B only (3) B and D only (4) B and C only

Q12.The graph between two temperature scales P and Q is shown in the figure. Between upper fixed point and lower fixed point there are 150 equal divisions of scale P and 100 divisions on scale Q. The relationship for conversion between the two scales is given by : . JEE Main 2023 (25 Jan Shift 2) JEE Main Previous Year Paper tQ (1) 150 = tP−180100 (2) 100tQ = tP−30150 (3) 180 tP = tQ−40100 (4) 100tQ = tP−180150

Q13.Given below are two statements: Statement I : The equivalent resistance of resistors in a series combination is smaller than least resistance used in the combination. Statement II : The resistivity of the material is independent of temperature. In the light of the above statements, choose the correct answer from the options given below: JEE Main 2023 (15 Apr Shift 1) JEE Main Previous Year Paper (1) Both Statement I and Statement II are false (2) Both Statement I and Statement II are true (3) Statement I is true but Statement II is false (4) Statement I is false but Statement II is true

Q13.A car P travelling at 20 m s−1 sounds its horn at a frequency of 400 Hz. Another car Q is travelling behind the first car in the same direction with a velocity 40 m s−1 . The frequency heard by the passenger of the car Q is approximately [Take, velocity of sound = 360 m s−1 ] (1) 421 Hz (2) 471 Hz (3) 485 Hz (4) 514 Hz

Q13.An electron is moving along the positive x-axis. If uniform magnetic field is applied parallel to the negative z- axis, then A.The electron will experience magnetic force along positive y-axis B.The electron will experience magnetic force along negative y-axis C.The electron will not experience any force in magnetic field D.The electron will continue to move along the positive x-axis E.The electron will move along circular path in magnetic field Choose the correct answer from the option given below: (1) A and E only (2) C and D only (3) B and E only (4) B and D only

Q13.A massless square loop, of wire of resistance 10 Ω, supporting a mass of 1 g, hangs vertically with one of its sides in a uniform magnetic field of 103 G, directed outwards in the shaded region. A dc voltage 𝑉 is applied to the loop. For what value of 𝑉, the magnetic force will exactly balance the weight of the supporting mass of 1 g? (If sides of the loop = 10 cm, 𝑔= 10 m s-2) . JEE Main 2023 (30 Jan Shift 1) JEE Main Previous Year Paper 1 (1) 10V (2) 100 V (3) 1 V (4) 10 V

Q13.A Carnot engine operating between two reservoirs has efficiency 1 . When the temperature of cold reservoir 3 raised by x , its efficiency decreases to 1 . The value of x , if the temperature of hot reservoir is 99° C , will be 6 (1) 16. 5 K (2) 33 K (3) 66 K (4) 62 K

Q13.At 300 K , the rms speed of oxygen molecules is √α+5α value of α will be (use π = 227 ) (1) 32 (2) 28 (3) 24 (4) 27

Q13.For particle P revolving round the centre O with radius of circular path r and regular velocity ω, as shown in below figure, the projection of OP on the x-axis at time t is JEE Main 2023 (08 Apr Shift 2) JEE Main Previous Year Paper (1) x(t) = r cos(ωt −π6 ) (2) x(t) = r cos(ωt + π6 ) (3) x(t) = r sin(ωt + π6 ) (4) x(t) = r cos(ωt)

Q13.Given below are two statements: Statement I: If the number of turns in the coil of a moving coil galvanometer is doubled then the current sensitivity becomes double. Statement II: Increasing current sensitivity of a moving coil galvanometer by only increasing the number of turns in the coil will also increase its voltage sensitivity in the same ratio In the light of the above statements, choose the correct answer from the options given below: (1) Statement I is true but Statement II is false (2) Statement I is false but Statement II is true (3) Both Statement I and Statement II are false (4) Both Statement I and Statement II are true

Q13.Given below are two statements: Statement I: For diamagnetic substance -1 ≤x < 0, where x is the magnetic susceptibility. Statement II: Diamagnetic substance when placed in an external magnetic field, tend to move from stronger to weaker part of the field. In the light of the above statements, choose the correct answer from the options give below. (1) Both Statement I and Statement II are False (2) Statement I is correct but Statement II is false (3) Statement I is incorrect but Statement II is true (4) Both Statement I and Statement II are true

Q13.Let γ1 be the ratio of molar specific heat at constant pressure and molar specific heat at constant volume of a monoatomic gas and γ2 be the similar ratio of diatomic gas. Considering the diatomic gas molecule as a rigid rotator, the ratio γ1 is: γ2 (1) 27 (2) 35 35 27 (3) 25 (4) 21 21 25

Q13.Find the magnetic field at the point P in figure. The curved portion is a semicircle connected to two long straight wires. JEE Main 2023 (01 Feb Shift 1) JEE Main Previous Year Paper 𝜇0𝑖 2 𝜇0𝑖 1 (1) 2𝑟1 + π (2) 2𝑟1 + π 𝜇0𝑖 1 1 𝜇0𝑖 1 1 (3) + (4) + 2𝑟 2 2π 2𝑟 2 π

Q13.A bar magnet with a magnetic moment 5 . 0 A m2 is placed in parallel position relative to a magnetic field of 0 . 4 T. The amount of required work done in turning the magnet form parallel to antiparallel position relative to the field direction is ________. (1) 4 J (2) 1 J (3) 2 J (4) Zero

Q13.If the r.m.s speed of chlorine molecule is 490 m s−1 at 27oC , the r.m.s speed of argon molecules at the same temperature will be (Atomic mass of argon = 39. 9 u , molecular mass of chlorine = 70. 9 u ) (1) 551. 7 m s−1 (2) 651. 7 m s−1 (3) 451. 7 m s−1 (4) 751. 7 m s−1