Practice Questions

Q9. A force is applied to a steel wire A , rigidly clamped at one end. As a result elongation in the wire is 0. 2 mm. If same force is applied to another steel wire B of double the length and a diameter 2. 4 times that of the wire A, the elongation in the wire B will be (wires having uniform circular cross sections) (1) 6. 06 × 10–2 mm (2) 2. 77 × 10–2 mm (3) 3. 0 × 10–2 mm (4) 6. 9 × 10–2 mm

Q9. Match List I with List II: List I List II (A)3 Translational degrees of freedom (I) Monoatomic gases (B) 3 Translational, 2 rotational degrees of freedoms (II) Polyatomic gases 3 Translational, 2 rotational and 1 vibrational degrees Rigid diatomic (C) (III) of freedom gases (D)3 Translational, 3 rotational and more than one (IV)Nonrigid diatomic vibrational degrees of freedom gases Choose the correct answer from the options given below: (1) A - I, B - III, C - IV, D - II (2) A - IV, B - III, C - II, D - I (3) A - IV, B - II, C - I, D - III (4) A - I, B - IV, C - III, D - II 𝐴

Q9. T is the time period of simple pendulum on the earth's surface. Its time period becomes xT when taken to a height R (equal to earth's radius) above the earth's surface. Then, the value of x will be: (1) 4 (2) 2 (3) 1 (4) 1 2 4

Q9. The correct relation between 𝛾= and temperature 𝑇 is : 𝐶𝑉 (1) 𝛾∝ 1 (2) 𝛾∝𝑇0 √𝑇 (3) 𝛾∝1 (4) 𝛾∝𝑇 𝑇

Q9. Eight equal drops of water are falling through air with a steady speed of 10 cm s−1 . If the drops coalesce, the new velocity is:- (1) 16 cm s−1 (2) 40 cm s−1 (3) 5 cm s−1 (4) 10 cm s−1 JEE Main 2023 (11 Apr Shift 2) JEE Main Previous Year Paper

Q9. Surface tension of a soap bubble is 2. 0 × 10−2 N m−1 . Work done to increase the radius of soap bubble from 3. 5 cm to 7 cm will be : [Take π = 227 ] (1) 0. 72 × 10−4 J (2) 5. 76 × 10−4 J (3) 18. 48 × 10−4 J (4) 9. 24 × 10−4 J JEE Main 2023 (29 Jan Shift 1) JEE Main Previous Year Paper

Q9. A travelling wave is described by the equation 𝑦𝑥, 𝑡= 0 . 05sin8𝑥- 4𝑡 m. The velocity of the wave is: [All the quantities are in SI unit] (1) 4 m s-1 (2) 2 m s-1 (3) 0 . 5 m s-1 (4) 8 m s-1

Q9. The weight of a body on the earth is 400 N. Then weight of the body when taken to a depth half of the radius of the earth will be: (1) 200 N (2) Zero (3) 100 N (4) 300 N

Q9. A metal block of mass m is suspended from a rigid support through a metal wire of diameter 14 mm. The tensile stress developed in the wire under equilibrium state is 7 × 105 N m–2 . The value of mass m is ______ kg. (Take g = 9. 8 m s−2 and π = 227 )

Q10.The Young's modulus of a steel wire of length 6 m and cross-sectional area 3 mm2 , is 2 × 1111 N/m2 . The wire is suspended from its support on a given planet. A block of mass 4 kg is attached to the free end of the JEE Main 2023 (01 Feb Shift 2) JEE Main Previous Year Paper wire. The acceleration due to gravity on the planet is 1 of its value on the earth. The elongation of wire is 4 (Take g on the earth = 10 m/s2 ): (1) 1 cm (2) 1 mm (3) 0. 1 mm (4) 0. 1 cm

Q10.A spherical drop of liquid splits into 1000 identical spherical drops. If ui is the surface energy of the original = ( 10x ). Then drop and uf is the total surface energy of the resulting drops, the (ignoring evaporation), ufui value of x is ______:

Q10.A fully loaded boeing aircraft has a mass of 5. 4 × 105 kg. Its total wing area is 500 m2 . It is in level flight with a speed of 1080 km h−1 . If the density of air ρ is 1. 2 kg m–3 , the fractional increase in the speed of the air on the upper surface of the wing relative to the lower surface in percentage will be ( g = 10 m s−2 ) (1) 16 (2) 6 (3) 8 (4) 10

Q10.A steel rod of length 1 m and cross-sectional area 10−4 m2 is heated from 0°C to 200°C without being allowed to extend or bend. The compressive tension produced in the rod is _____ ×104 N . (Given Young's modulus of steel = 2 × 1011 N m−2 , coefficient of linear expansion = 10−5 K−1 )

Q10.Glycerin of density 1. 25 × 103 kg m–3 is flowing through the conical section of pipe. The area of cross- section of the pipe at its ends are 10 cm2 and 5 cm2 and pressure drop across its length is 3 N m–2 . The rate of flow of glycerine through the pipe is x × 10–5 m3 s–1 . The value of x is _____.

Q10.A water heater of power 2000 W is used to heat water. The specific heat capacity of water is 4200 J kg−1 K−1 . The efficiency of heater is 70%. Time required to heat 2 kg of water from 10°C to 60°C is _____ s . (Assume that the specific heat capacity of water remains constant over the temperature range of the water).

Q10.The elastic potential energy stored in a steel wire of length 20 m stretched through 2 cm is 80 J. The cross sectional area of the wire is _____ mm2. (Given, Y = 2. 0 × 1011 N m–2 )

Q10.The maximum potential energy of a block executing simple harmonic motion is 25 J. A is amplitude of 𝐴 oscillation. At 2, the kinetic energy of the block is (1) 37 . 5 J (2) 9 . 75 J (3) 18 . 75 J (4) 12 . 5 J

Q10.A particle executes SHM of amplitude 𝐴. The distance from the mean position when its kinetic energy becomes equal to its potential energy is: (1) 1 (2) 2𝐴 √2𝐴 (3) √2𝐴 (4) 12𝐴

Q10.The pressure ( 𝑃) and temperature ( 𝑇) relationship of an ideal gas obeys the equation 𝑃𝑇2 = constant. The volume expansion coefficient of the gas will be : 3 (1) 3𝑇2 (2) 𝑇2 3 3 (3) (4) 𝑇3 𝑇

Q10.A faulty thermometer reads 5°C in melting ice and 95°C in steam. The correct temperature on absolute scale will be ______ K when the faulty thermometer reads 41°C.

Q10.A particle executes S.H.M. of amplitude 𝐴 along 𝑥-axis. At 𝑡= 0, the position of the particle is 𝑥= and it 2 moves along positive 𝑥-axis. The displacement of particle in time 𝑡 is 𝑥= 𝐴 sin𝜔𝑡 + 𝛿, then the value 𝛿 will be (1) 𝜋 (2) 𝜋 2 6 𝜋 𝜋 (3) (4) 3 4

Q10.A body cools from 60°C to 40°C in 6 minutes. If, temperature of surroundings is 10°C . Then, after the next 6 minutes, its temperature will be ______ °C.

Q10.The distance between two plates of a capacitor is 𝑑 and its capacitance is 𝐶1, when air is the medium between 2𝑑 the plates. If a metal sheet of thickness and of the same area as plate is introduced between the plates, the 3 𝐶2 capacitance of the capacitor becomes 𝐶2 . The ratio is 𝐶1 (1) 3 : 1 (2) 2 : 1 (3) 4 : 1 (4) 1 : 1

Q10.As shown in the figure, in an experiment to determine Young's modulus of a wire, the extension-load curve is plotted. The curve is a straight line passing through the origin and makes an angle of 45° with the load axis. The length of wire is 62. 8 cm and its diameter is 4 mm. The Young's modulus is found to be x × 104 N m−2 The value of x is _______.

Q10.In a linear Simple Harmonic Motion (SHM) (A) Restoring force is directly proportional to the displacement. (B) The acceleration and displacement are opposite in direction. (C) The velocity is maximum at mean position. (D) The acceleration is minimum at extreme points. Choose the correct answer from the options given below: (1) (C) and (D) only (2) (A), (C) and (D) only (3) (A), (B) and (C) only (4) (A), (B) and (D) only