Practice Questions

Q11. The figure shows a liquid of given density flowing steadily in horizontal tube of varying cross-section. Cross- sectional areas at A is 1. 5 cm2, and B is 25 mm2, if the speed of liquid at B is 60 cm s−1 then (PA–PB) is (Given PA and PB are liquid pressures at A and B points. Density ρ = 1000 kg m−3 A and B are on the axis of tube) (1) 135 Pa (2) 27 Pa (3) 175 Pa (4) 36 Pa 5 ) 2 v, when v is the average

Q11. A 10 𝜇C charge is divided into two parts and placed at 1 cm distance so that the repulsive force between them is maximum. The charges of the two parts are: (1) 7𝜇C, 3𝜇C (2) 8𝜇C, 2𝜇C (3) 5𝜇C, 5𝜇C (4) 9𝜇C, 1𝜇C

Q11.An air bubble of volume 1 cm3 rises from the bottom of a lake 40 m deep to the surface at a temperature of 12°C. The atmospheric pressure is 1 × 105 Pa, the density of water is 1000 kg m−3 and g = 10 m s−2. There is no difference of the temperature of water at the depth of 40 m and on the surface. The volume of air bubble when it reaches the surface will be (1) 2 cm3 (2) 3 cm3 (3) 4 cm3 (4) 5 cm3

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.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.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.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 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.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.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.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

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.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.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.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 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 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.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.A flask contains hydrogen and oxygen in the ratio of 2 : 1 by mass at temperature 27 °C. The ratio of average kinetic energy per molecule of hydrogen and oxygen respectively is : (1) 2 : 1 (2) 1 : 1 (3) 1 : 4 (4) 4 : 1

Q12.The temperature at which the kinetic energy of oxygen molecules becomes double than its value at 27°C is (1) 927°C (2) 327°C (3) 1227°C (4) 627°C

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

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.For a solid rod, the Young's modulus of elasticity is 3. 2 × 1011 N m−2 and density is 8 × 103 kg m−3 . The velocity of longitudinal wave in the rod will be (1) 145. 75 × 103 m s−1 (2) 3. 65 × 103 m s−1 (3) 18. 96 × 103 m s−1 (4) 6. 32 × 103 m s−1

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.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