Practice Questions

Q8. The acceleration due to gravity at height h above the earth if h ≪R (Radius of earth) is given by − 2R2 (1) g′ = g(1 h2 ) (2) g′ = g(1 − 2Rh ) (3) g′ = g(1 −2hR ) (4) g′ = g(1 −2h2R2 )

Q8. A thermodynamic system is taken through cyclic process. The total work done in the process is : JEE Main 2023 (15 Apr Shift 1) JEE Main Previous Year Paper (1) 200 J (2) 300 J (3) 100 J (4) Zero

Q8. The height of liquid column raised in a capillary tube of certain radius when dipped in liquid 𝐴 vertically is, 5 cm. If the tube is dipped in a similar manner in another liquid 𝐵 of surface tension and density double the JEE Main 2023 (30 Jan Shift 1) JEE Main Previous Year Paper values of liquid 𝐴, the height of liquid column raised in liquid B would be ______ m. (1) 0 . 20 (2) 0 . 5 (3) 0 . 05 (4) 0 . 10

Q8. A body weight W , is projected vertically upwards from earth's surface to reach a height above the earth which is equal to nine times the radius of earth. The weight of the body at that height will be: (1) W (2) W 91 100 (3) W (4) W 9 3

Q9. For a periodic motion represented by the equation 𝑦= sinω𝑡+ cosω𝑡 the amplitude of the motion is (1) 1 (2) 0 . 5 (3) 2 (4) √2

Q9. Heat is given to an ideal gas in an isothermal process. A. Internal energy of the gas will decrease. B. Internal energy of the gas will increase. C. Internal energy of the gas will not change. D. The gas will do positive work. E. The gas will do negative work. Choose the correct answer from the options given below : (1) A and E only (2) B and D only (3) C and E only (4) C and D only

Q9. Every planet revolves around the sun in an elliptical orbit : A. The force acting on a planet is inversely proportional to square of distance from sun. B. Force acting on planet is inversely proportional to product of the masses of the planet and the sun. C. The centripetal force acting on the planet is directed away from the sun. D. The square of time period of revolution of planet around sun is directly proportional to cube of semi-major axis of elliptical orbit. Choose the correct answer from the options given below : (1) A and D only (2) C and D only (3) B and C only (4) A and C only

Q9. A source supplies heat to a system at the rate of 1000 W . If the system performs work at a rate of 200 W . The rate at which internal energy of the system increases is (1) 600 W (2) 800 W (3) 500 W (4) 1200 W

Q9. A flask contains Hydrogen and Argon in the ratio 2 : 1 by mass. The temperature of the mixture is 30°C . The ratio of average kinetic energy per molecule of the two gases ( KhydrogenKargon ) is: (Given : Atomic Weight of Ar = 39. 9 ) (1) 2 (2) 1 (3) 39. 9 (4) 39.92

Q9. The time period of a satellite of earth is 24 hours. If the separation between the earth and the satellite is decreased to one fourth of the previous value, then its new time period will become. (1) 4 hours (2) 6 hours (3) 12 hours (4) 3 hours

Q9. A hydraulic automobile lift is designed to lift vehicles of mass 5000 kg. The area of cross section of the cylinder carrying load is 250 cm2 . The maximum pressure the smaller piston would have to bear is [Assume g = 10 m s−2 ] (1) 20 × 106 Pa (2) 2 × 105 Pa (3) 200 × 106 Pa (4) 2 × 106 Pa

Q10.Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R Assertion (A) : Steel is used in the construction of buildings and bridges. Reason (R) : Steel is more elastic and its elastic limit is high. In the light of above statements, choose the most appropriate answer from the options given below (1) Both A and R are correct and R is the correct (2) Both A and R are correct but R is NOT the explanation of A correct explanation of A (3) A is correct but R is not correct (4) A is not correct but R is correct

Q10.The number of air molecules per cm3 is increased from 3 × 1019 to 12 × 1019 . The ratio of collision frequency of air molecules before and after the increase in number respectively is : (1) 0 . 75 (2) 1 . 25 (3) 0 . 50 (4) 0 . 25

Q10.A steel wire with mass per unit length 7 . 0 × 10 – 3 kg m – 1 is under tension of 70 N. The speed of transverse waves in the wire will be: (1) 200π m s-1 (2) 100 m s-1 (3) 10 m s-1 (4) 50 m s-1

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

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

Q12.A bicycle tyre is filled with air having pressure of 270 kPa at 27°C. The approximate pressure of the air in the tyre when the temperature increases to 36°C is (1) 270 kPa (2) 262 kPa (3) 278 kPa (4) 360 kPa

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.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.The temperature at which the kinetic energy of oxygen molecules becomes double than its value at 27°C is (1) 927°C (2) 327°C (3) 1227°C (4) 627°C

Q13.For a simple harmonic motion in a mass spring system shown, the surface is frictionless. When the mass of the block is 1 kg, the angular frequency is ω1 . When the mass block is 2 kg the angular frequency is ω2 . The ratio JEE Main 2023 (30 Jan Shift 2) JEE Main Previous Year Paper ω2 is : ω1 (1) √2 (2) 1 √2 (3) 2 (4) 12

Q13.Match List I with List II : List I List II AIsothermal I Work done by the gas decreases internal energy Process B Adiabatic Process II No change in internal energy The heat absorbed goes partly to increase internal energy and partly to do C Isochoric Process III work DIsobaric Process IVNo work is done on or by the gas Choose the correct answer from the options given below : (1) A-II, B-I, C-III, D-IV (2) A-II, B-I, C-IV, D-III (3) A-I, B-II, C-IV, D-III (4) A-I, B-II, C-III, D-IV

Q13.For a solid rod, the Young's modulus of elasticity is 3. 2 × 1011 N m−2 and density is 8 × 103 kg m−3 . The velocity of longitudinal wave in the rod will be (1) 145. 75 × 103 m s−1 (2) 3. 65 × 103 m s−1 (3) 18. 96 × 103 m s−1 (4) 6. 32 × 103 m s−1

Q14.A mass m attached to free end of a spring executes SHM with a period of 1 s. If the mass is increased by 3 kg the period of oscillation increases by one second, the value of mass m is ________ kg.

Q14.The amplitude of magnetic field in an electromagnetic wave propagating along 𝑦-axis is 6 . 0 × 10 – 7 T. The maximum value of electric field in the electromagnetic wave is (1) 2 × 1015 V m – 1 (2) 180 V m – 1 (3) 6 . 0 × 10 – 7 V m – 1 (4) 5 × 1014 V m – 1