Practice Questions

Q8. The temperature of a gas is −78∘C and the average translational kinetic energy of its molecules is K. The temperature at which the average translational kinetic energy of the molecules of the same gas becomes 2 K is : (1) 127∘C (2) 117∘C (3) −39∘C (4) −78∘C

Q9.Match List I with List II : (1) (A)-(III), (B)-(IV), (C)-(I), (D)-(II) (2) (A)-(II), (B)-(I), (C)-(IV), (D)-(III) (3) (A)-(I), (B)-(II), (C)-(III), (D)-(IV) (4) (A)-(I), (B)-(IV), (C)-(II), (D)-(III)

Q9. The total kinetic energy of 1 mole of oxygen at 27°C is : [Use universal gas constant (R) = 8 . 31 J mol-1 K-1 ] (1) 6845 . 5 J (2) 5942 . 0 J (3) 6232 . 5 J (4) 5670 . 5 J

Q9. The volume of an ideal gas (γ = 1.5) is changed adiabatically from 5 litres to 4 litres. The ratio of initial pressure to final pressure is: JEE Main 2024 (09 Apr Shift 1) JEE Main Previous Year Paper (1) 16 (2) 4 25 5 (3) 8 (4) 2 5√5 √5

Q9. Given below are two statements : Statement (I) : The mean free path of gas molecules is inversely proportional to square of molecular diameter. Statement (II) : Average kinetic energy of gas molecules is directly proportional to absolute temperature of gas. 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) Both Statement I and Statement II are false (3) Both Statement I and Statement II are true (4) Statement I is false but Statement II is true

Q9. Two vessels A and B are of the same size and are at same temperature. A contains 1 g of hydrogen and B contains 1 g of oxygen. PA and PB are the pressures of the gases in A and B respectively, then PA is : PB (1) 16 (2) 8 (3) 4 (4) 32

Q9. If the root mean square velocity of hydrogen molecule at a given temperature and pressure is 2 km s-1, the root mean square velocity of oxygen at the same condition in km s-1 is: (1) 2 . 0 (2) 0 . 5 (3) 1 . 5 (4) 1 . 0 Q10.𝐶1 and 𝐶2 are two hollow concentric cubes enclosing charges 2𝑄 and 3𝑄 respectively as shown in figure. The ratio of electric flux passing through 𝐶1 and 𝐶2 is: (1) 2 : 5 (2) 5 : 2 (3) 2 : 3 (4) 3 : 2

Q9. The translational degrees of freedom (ft) and rotational degrees of freedom (fr) of CH4 molecule are: (1) ft = 2 and fr = 2 (2) ft = 3 and fr = 3 (3) ft = 3 and fr = 2 (4) ft = 2 and fr = 3

Q9. The temperature of a gas having 2. 0 × 1025 molecules per cubic meter at 1. 38 atm (Given, k = 1. 38 × 10−23J K−1) is : (1) 500 K (2) 200 K (3) 100 K (4) 300 K

Q9. Five charges +q, +5q, −2q, +3q and −4q are situated as shown in the figure. The electric flux due to this configuration through the surface S is : (1) 4q (2) 5q ϵ0 ϵ0 (3) q (4) 3q ϵ0 ϵ0

Q9. If n is the number density and d is the diameter of the molecule, then the average distance covered by a molecule between two successive collisions (i.e. mean free path) is represented by : (1) √2nπd2 (2) 1 √2nπd2 (3) 1 (4) 1 √2nπd2 √2n2π2d2

Q9. A sample contains mixture of helium and oxygen gas. The ratio of root mean square speed of helium and oxygen in the sample, is: (1) 1 (2) 2√2 32 1 (3) 1 (4) 1 2√2 4

Q10.A mixture of one mole of monoatomic gas and one mole of a diatomic gas (rigid) are kept at room temperature (27∘C). The ratio of specific heat of gases at constant volume respectively is: (1) 7 (2) 3 5 5 (3) 5 (4) 3 3 2

Q10.Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason(R) Assertion (A) : Work done by electric field on moving a positive charge on an equipotential surface is always zero. Reason (R) : Electric lines of forces are always perpendicular to equipotential surfaces. In the light of the above statements, choose the most appropriate answer from the options given below : (1) Both (A) and (R) are correct but (R) is not the (2) (A) is correct but (R) is not correct correct explanation of (A) (3) (A) is not correct but (R) is correct (4) Both (A) and (R) are correct and (R) is the correct explanation of (A)

Q10.The vehicles carrying inflammable fluids usually have metallic chains touching the ground : (1) To protect tyres from catching dirt from ground (2) To alert other vehicles (3) It is a custom (4) To conduct excess charge due to air friction to ground and prevent sparking

Q10.The given figure represents two isobaric processes for the same mass of an ideal gas, then (1) 𝑃2 ≥𝑃1 (2) 𝑃2 > 𝑃1 (3) 𝑃1 = 𝑃2 (4) 𝑃1 > 𝑃2

Q10.A plane progressive wave is given by y = 2 cos 2π(330t −x)m . The frequency of the wave is : (1) 330 Hz (2) 660 Hz (3) 340 Hz (4) 165 Hz

Q10.In simple harmonic motion, the total mechanical energy of given system is E . If mass of oscillating particle P is doubled then the new energy of the system for same amplitude is: (1) E (2) E/√2 (3) 2E (4) E√2

Q10.On celcius scale the temperature of body increases by 40∘C . The increase in temperature on Fahrenheit scale is : (1) 68∘F (2) 75∘F (3) 72∘F (4) 70∘F

Q10.The electrostatic potential due to an electric dipole at a distance r varies as : (1) r (2) 1 r2 (3) 1 (4) 1 r3 r

Q10.Force between two point charges 𝑞1 and 𝑞2 placed in vacuum at 𝑟 cm apart is 𝐹. Force between them when placed in a medium having dielectric 𝐾= 5 at 𝑟 cm apart will be: 5 𝐹 (1) (2) 5𝐹 25 (3) 𝐹 (4) 25𝐹 5

Q11.By what percentage will the illumination of the lamp decrease if the current drops by 20%? (1) 46% (2) 26% (3) 36% (4) 56%

Q11. The parameter that remains the same for molecules of all gases at a given temperature is : (1) kinetic energy (2) momentum (3) mass (4) speed

Q11.A potential divider circuit is shown in figure. The output voltage V0 is (1) 4 V (2) 2 mV (3) 0. 5 V (4) 12 mV JEE Main 2024 (30 Jan Shift 1) JEE Main Previous Year Paper

Q11.The number of electrons flowing per second in the filament of a 110 W bulb operating at 220 V is : ( Given e = 1.6 × 10−19C) (1) 6.25 × 1017 (2) 1.25 × 1019 (3) 6.25 × 1018 (4) 31.25 × 1017 JEE Main 2024 (06 Apr Shift 2) JEE Main Previous Year Paper