Practice Questions

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 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. The resistances of the platinum wire of a platinum resistance thermometer at the ice point and steam point are 8Ω and 10Ω respectively. After inserting in a hot bath of temperature 400∘C , the resistance of platinum wire is : (1) 10Ω (2) 8Ω (3) 16Ω (4) 2Ω

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. The average kinetic energy of a monatomic molecule is 0. 414 eV at temperature: JEE Main 2024 (27 Jan Shift 1) JEE Main Previous Year Paper (Use KB = 1. 38 × 10−23 J mol−1 K−1 ) (1) 3000 K (2) 3200 K (3) 1600 K (4) 1500 K

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. Energy of 10 non rigid diatomic molecules at temperature T is : (1) 70 KBT (2) 35 KBT (3) 7 2 RT (4) 35RT

Q9. The pressure and volume of an ideal gas are related as 𝑃𝑉 32 = 𝐾 (Constant). The work done when the gas is taken from state 𝐴𝑃1, 𝑉1, 𝑇1 to state 𝐵𝑃2, 𝑉2, 𝑇2 is : (1) 2 ( 𝑃1𝑉1 - 𝑃2𝑉2 ) (2) 2 ( 𝑃2𝑉2 - 𝑃1𝑉1 ) (3) 2√𝑃1𝑉1 −√𝑃2𝑉2 (4) 2𝑃2√𝑉2 −𝑃1√𝑉1

Q10.The effective resistance between A and B, if resistance of each resistor is R, will be (1) 8R (2) 5R 3 3 (3) 4R (4) 2 R 3 3

Q10.A bulb and a capacitor are connected in series across an ac supply. A dielectric is then placed between the plates of the capacitor. The glow of the bulb: (1) increases (2) decreases (3) remains same (4) becomes zero

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.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.An electric charge 10−6 μC is placed at origin (0, 0) m of X −Y co-ordinate system. Two points P and Q are situated at m and m respectively. The potential difference between the points P and Q (√3, √3) (√6, 0) will be : (1) √3 V (2) √6 V (3) 0 V (4) 3 V

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.Two charges of 5Q and −2Q are situated at the points (3a, 0) and (−5a, 0) respectively. The electric flux through a sphere of radius 4a having centre at origin is: (1) 2Q (2) 5Q ε0 ε0 (3) 7Q (4) 3Q ε0 ε0

Q10.Two moles of a monoatomic gas is mixed with six moles of a diatomic gas. The molar specific heat of the mixture at constant volume is : 9 7 (1) 4𝑅 (2) 4𝑅 (3) 3 (4) 5 2𝑅 2𝑅

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. N moles of a polyatomic gas (f = 6) must be mixed with two moles of a monoatomic gas so that the mixture behaves as a diatomic gas. The value of N is: (1) 6 (2) 3 (3) 4 (4) 2 N C−1 . The electric flux through a surface area 30ˆi m2 lying in

Q10.Two identical conducting spheres P and S with charge Q on each, repel each other with a force 16 N. A third identical uncharged conducting sphere R is successively brought in contact with the two spheres. The new force of repulsion between P and S is : (1) 1 N (2) 6 N (3) 12 N (4) 4 N

Q10.A particle of charge -𝑞 and mass 𝑚 moves in a circle of radius 𝑟 around an infinitely long line charge of linear density +𝜆. Then time period will be given as: (Consider 𝑘 as Coulomb's constant) (1) 𝑇2 = 4𝜋2 2𝑘𝜆𝑞𝑟3𝑚 (2) 𝑇= 2𝜋𝑟√ 2𝑘𝜆𝑞𝑚 (3) 𝑇= 1 𝑚 (4) 𝑇= 1 2𝑘𝜆𝑞 2𝜋𝑟√ 2𝑘𝜆𝑞 2𝜋√ 𝑚

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

Q10.The specific heat at constant pressure of a real gas obeying PV 2 = RT equation is: (1) R 3 + CV (2) CV + R (3) CV + 2VR (4) R

Q11.Ques: σ is the uniform surface charge density of a thin spherical shell of radius R. The electric field at any point on the surface of the spherical shell is : (1) σ/ϵoR (2) σ/ϵo (3) σ/4ϵo (4) σ/2ϵo

Q11.Two identical capacitors have same capacitance 𝐶. One of them is charged to the potential 𝑉 and other to the potential 2𝑉. The negative ends of both are connected together. When the positive ends are also joined together, the decrease in energy of the combined system is : 1 (1) 4𝐶𝑉2 (2) 2𝐶𝑉2 (3) 12𝐶𝑉2 (4) 34𝐶𝑉2