Practice Questions

Q8. A diatomic gas (γ = 1.4) does 100 J of work in an isobaric expansion. The heat given to the gas is : (1) 250 J (2) 150 J (3) 350 J (4) 490 J

Q8. At which temperature the r.m.s. velocity of a hydrogen molecule equal to that of an oxygen molecule at 47°C ? (1) 80 K (2) −73 K (3) 4 K (4) 20 K

Q8. A thermodynamic system is taken from an original state A to an intermediate state B by a linear process as shown in the figure. Its volume is then reduced to the original value from B to C by an isobaric process. The total work done by the gas from A to B and B to C would be : JEE Main 2024 (29 Jan Shift 1) JEE Main Previous Year Paper (1) 33800 J (2) 2200 J (3) 600 J (4) 800 J

Q8. Four identical particles of mass 𝑚 are kept at the four corners of a square. If the gravitational force exerted on 2√2 + 1 𝐺𝑚2 one of the masses by the other masses is , the length of the sides of the square is 32 𝐿2 𝐿 (1) (2) 4𝐿 2 (3) 3𝐿 (4) 2𝐿

Q8. A small liquid drop of radius R is divided into 27 identical liquid drops. If the surface tension is T , then the work done in the process will be : (1) 8πR2T (2) 3πR2T (3) 1 πR2T (4) 4πR2T 8

Q8. A diatomic gas ( 𝛾= 1 . 4 ) does 200 J of work when it is expanded isobarically. The heat given to the gas in the process is : (1) 850 J (2) 800 J (3) 600 J (4) 700 J

Q9. Two different adiabatic paths for the same gas intersect two isothermal curves as shown in P-V diagram. The relation between the ratio Va and the ratio Vb is: Vd Vc (1) Va ≠Vb (2) Va = Vb Vd Vc Vd Vc (3) Va Vb −1 (4) Va Vb 2 = = Vd ( Vc ) Vd ( Vc )

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. 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

Q9. If three moles of monoatomic gas 𝛾= 5 is mixed with two moles of a diatomic gas 𝛾= 7 the value of adiabatic 3 5, exponent 𝛾 for the mixture is: (1) 1 . 75 (2) 1 . 40 (3) 1 . 52 (4) 1 . 35

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 thermodynamical process are shown in the figure. The molar heat capacity for process A and B are CA and CB . The molar heat capacity at constant pressure and constant volume are represented by CP and CV , respectively. Choose the correct statement. (1) CP > CB > CV (2) CA = 0 and CB = ∞ (3) CP > CV > CA = CB (4) CA > CP > CV

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. Two conductors have the same resistances at 0 °C but their temperature coefficients of resistance are 𝛼1 and 𝛼2 . The respective temperature coefficients for their series and parallel combinations are : (1) 𝛼1 + 𝛼2, 𝛼1 + 𝛼2 (2) 𝛼1 + 𝛼2 , 𝛼1 + 𝛼2 2 2 2 𝛼1 𝛼2 𝛼1 + 𝛼2 (4) (3) 𝛼1 + 𝛼2, , 𝛼1 + 𝛼2 2 𝛼1 + 𝛼2

Q9. The speed of sound in oxygen at S.T.P. will be approximately: (Given, 𝑅= 8 . 3 J K-1, 𝛾= 1 . 4) (1) 310 m s-1 (2) 333 m s-1 (3) 341 m s-1 (4) 325 m s-1

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. 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.Given below are two statements : Statement I : When a capillary tube is dipped into a liquid, the liquid neither rises nor falls in the capillary. The contact angle may be 0∘ . Statement II : The contact angle between a solid and a liquid is a property of the material of the solid and liquid as well. In the light of the above statement, choose the correct answer from the options given below. (1) Both Statement I and Statement II are false (2) Both Statement I and Statement II are true (3) Statement I is false but Statement II is true (4) Statement I is true and Statement II is false

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.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.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.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.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

Q11. The heat absorbed by a system in going through the given cyclic process is : JEE Main 2024 (05 Apr Shift 1) JEE Main Previous Year Paper (1) 19.6 J (2) 61.6 J (3) 616 J (4) 431.2 J