Practice Questions

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.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.Two long straight wires 𝑃 and 𝑄 carrying equal current 10 A each were kept parallel to each other at 5 cm distance. Magnitude of magnetic force experienced by 10 cm length of wire 𝑃 is 𝐹1. If distance between wires is halved and currents on them are doubled, force 𝐹2 on 10 cm length of wire 𝑃 will be: (1) 8𝐹1 (2) 10 𝐹1 𝐹1 𝐹1 (3) (4) 8 10

Q12.For three low density gases A, B, C pressure versus temperature graphs are plotted while keeping them at constant volume, as shown in the figure The temperature corresponding to the point ′K′ is: (1) −273°C (2) −100°C (3) –373°C (4) −40°C

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 temperature of an ideal gas is increased from 200 K to 800 K . If r.m.s. speed of gas at 200 K is v0 . Then, r.m.s. speed of the gas at 800 K will be: (1) v0 (2) v0 4 (3) 4v0 (4) 2v0

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.Two identical heater filaments are connected first in parallel and then in series. At the same applied voltage, the ratio of heat produced in same time for parallel to series will be: (1) 1: 4 (2) 4: 1 (3) 2: 1 (4) 1: 2 JEE Main 2023 (11 Apr Shift 1) JEE Main Previous Year Paper

Q12.The root mean square speed of molecules of nitrogen gas at 27°C is approximately: (Given mass of a nitrogen molecule = 4. 6 × 10−26 kg and take Boltzmann constant kB = 1. 4 × 10−23J K−1 ) (1) 27. 4 m s−1 (2) 91 m s−1 (3) 1260 m s−1 (4) 523 m s−1

Q12.For designing a voltmeter of range 50 V and an ammeter of range 10 mA using a galvanometer which has a coil of resistance 54 Ω showing a full scale deflection for 1 mA as in figure. (A) for voltmeter R ≈50 kΩ (B) for ammeter r ≈0. 2 Ω (C) for ammeter r ≈6 Ω (D) for voltmeter R ≈5 kΩ (E) for voltmeter R ≈500 Ω Choose the correct answer from the options given below: (1) (A) and (C) (2) (C) and (E) (3) (C) and (D) (4) (A) and (B)

Q12.A Carnot engine with efficiency 50% takes heat from a source at 600 K . In order to increase the efficiency to 70% , keeping the temperature of sink same, the new temperature of the source will be: (1) 360 K (2) 1000 K (3) 900 K (4) 300 K

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.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 bicycle tyre is filled with air having pressure of 270 kPa at 27°C. The approximate pressure of the air in the tyre when the temperature increases to 36°C is (1) 270 kPa (2) 262 kPa (3) 278 kPa (4) 360 kPa

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.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.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 drift velocity of electrons for a conductor connected in an electrical circuit is 𝑉𝑑. The conductor is now replaced by another conductor with same material and same length but double the area of cross-section. The applied voltage remains same. The new drift velocity of electrons will be JEE Main 2023 (31 Jan Shift 1) JEE Main Previous Year Paper 𝑉𝑑 (1) 𝑉𝑑 (2) 2 (3) 𝑉𝑑 (4) 2𝑉𝑑 4

Q12.In the network shown below, the charge accumulated in the capacitor in steady state will be: (1) 10 . 3 𝜇C (2) 4 . 8 𝜇C (3) 12 𝜇C (4) 7 . 2𝜇C

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.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.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

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.For a simple harmonic motion in a mass spring system shown, the surface is frictionless. When the mass of the block is 1 kg, the angular frequency is ω1 . When the mass block is 2 kg the angular frequency is ω2 . The ratio JEE Main 2023 (30 Jan Shift 2) JEE Main Previous Year Paper ω2 is : ω1 (1) √2 (2) 1 √2 (3) 2 (4) 12

Q13.Match List I with List II : List I List II AIsothermal I Work done by the gas decreases internal energy Process B Adiabatic Process II No change in internal energy The heat absorbed goes partly to increase internal energy and partly to do C Isochoric Process III work DIsobaric Process IVNo work is done on or by the gas Choose the correct answer from the options given below : (1) A-II, B-I, C-III, D-IV (2) A-II, B-I, C-IV, D-III (3) A-I, B-II, C-IV, D-III (4) A-I, B-II, C-III, D-IV