Practice Questions

Q11.For a uniformly charged thin spherical shell, the electric potential 𝑉 radially away from the centre 𝑂 of shell can be graphically represented as (1) (2) (3) (4) JEE Main 2023 (06 Apr Shift 1) JEE Main Previous Year Paper

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. 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.Heat energy of 735 J is given to a diatomic gas allowing the gas to expand at constant pressure. Each gas molecule rotates around an internal axis but do not oscillate. The increase in the internal energy of the gas will be: (1) 525 J (2) 441 J (3) 572 J (4) 735 J

Q11.The equivalent capacitance of the combination shown is (1) 2 C (2) 5 C 3 C (3) (4) 4 C 2

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

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.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.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 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

Q11.Work done by a Carnot engine operating between temperatures 127°C and 27°C is 2 kJ . The amount of heat transferred to the engine by the reservoir is: (1) 8 kJ (2) 2. 67 kJ (3) 2 kJ (4) 4 kJ

Q11.The surface of water in a water tank of cross section area 750 cm2 on the top of a house is h m. above the tap level. The speed of water coming out through the tap of cross section area 500 mm2 is 30 cm s−1 . At that instant, dh is x × 10−3 m s−1 . The value of x will be ______. dt

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.A metal block of base area 0. 20 m2 is placed on a table, as shown in figure. A liquid film of thickness 0. 25 mm is inserted between the block and the table. The block is pushed by a horizontal force of 0. 1 N and moves with a constant speed. If the viscosity of the liquid is 5. 0 × 10–3 Pl, the speed of block is ______ ×10−3 m s−1 .

Q11. Given below are two statements. One is labelled as Assertion A and the other is labelled as Reason R. Assertion A : If dQ and dW represent the heat supplied to the system and the work done on the system respectively. Then according to the first law of thermodynamics dQ = dU −dW . Reason R : First law of thermodynamics is based on law of conservation of energy. In the light of the above statements, choose the correct answer from the option given below : (1) A is correct but R is not correct (2) A is not correct but R is correct (3) Both A and R are correct and R is the correct (4) Both A and R are correct but R is not the correct explanation of A explanation of A

Q11.The electric field due to a short electric dipole at a large distance (r) from center of dipole on the equatorial plane varies with distance as : (1) r (2) 1 r2 (3) 1 (4) 1r r3

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.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 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.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 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.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.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.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