Practice Questions

Q11.As shown in the figure, a network of resistors is connected to a battery of 24 V with an internal resistance of 3 𝛺. The currents through the resistors 𝑅4 and 𝑅5 are 𝐼4 and 𝐼5 respectively. The values of 𝐼4 and 𝐼5 are: 8 2 24 6 (1) 𝐼4 = 5 A and I5 = 5 A (2) 𝐼4 = 5 A and 𝐼5 = 5 A (3) 𝐼4 = 6 A and 𝐼5 = 24 A (4) 𝐼4 = 2 A and 𝐼5 = 8 A 5 5 5 5

Q11.A spherical ball of radius 1 mm and density 10. 5 g cc−1 is dropped in glycerine of coefficient of viscosity 9. 8 poise and density 1. 5 g cc−1 . Viscous force on the ball when it attains constant velocity is 3696 × 10−x N . The value of x is (Given, g = 9. 8 m s−2 and π = 227 )

Q11.According to law of equipartition of energy the molar specific heat of a diatomic gas at constant volume where the molecule has one additional vibrational mode is :- (1) 9 R (2) 5 R 2 2 (3) 3 R (4) 7 R 2 2

Q11.Given below are two statements : one is labelled as Assertion A and the other is labelled as Reason R. Assertion A : Efficiency of a reversible heat engine will be highest at –273 °C temperature of cold reservoir. Reason R : The efficiency of Carnot’s engine depends not only on temperature of cold reservoir but it depends on the temperature of hot reservoir too and is given as η = (1 −T2T1 ) In the light of the above statements, choose the correct answer from the options given below : (1) A is true but R is false (2) Both A and R are true but R is NOT the correct explanation of A (3) A is false but R is true (4) Both A and R are true and R is the correct explanation of A

Q11.A body cools in 7 minutes from 60oC to 40oC. The temperature of the surrounding is 10oC. The temperature of the body after the next 7 minutes will be (1) 30oC (2) 32oC (3) 34oC (4) 28oC

Q11.A parallel plate capacitor of capacitance 2 F is charged to a potential 𝑉. The energy stored in the capacitor is 𝐸1. The capacitor is now connected to another uncharged identical capacitor in parallel combination. The 𝐸2 energy stored in the combination is 𝐸2. The ratio is 𝐸1 (1) 2: 1 (2) 2: 3 (3) 1: 2 (4) 1: 4

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. A bowl filled with very hot soup cools from 98°C to 86∘C in 2 minutes when the room temperature is 22∘C . How long it will take to cool from 75∘C to 69∘C ? (1) 2 minute (2) 1. 4 minute (3) 0. 5 minute (4) 1 minute

Q11.Two isolated metallic solid spheres of radii 𝑅 and 2𝑅 are charged such that both have same charge density 𝜎 . The spheres are then connected by a thin conducting wire. If the new charge density of the bigger sphere is 𝜎'. 𝜎' The ratio is : 𝜎 9 4 (1) (2) 4 3 5 5 (3) (4) 3 6

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.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.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.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.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.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 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 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.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.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.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

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.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.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.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