Practice Questions

Q23.A liquid of density 750 kg m−3 flows smoothly through a horizontal pipe that tapers in cross-sectional area from A1 = 1. 2 × 10−2 m2 to A2 = A12 . The pressure difference between the wide and narrow sections of the pipe is 4500 Pa . The rate of flow of liquid is _____ ×10−3 m3 s−1 .

Q23.In an experiment to determine the Young's modulus, steel wires of five different lengths ( 1, 2, 3, 4 and 5 ) but of same cross-section (2 mm2) were taken and curves between extension and load were obtained. The slope JEE Main 2022 (27 Jul Shift 2) JEE Main Previous Year Paper (extension/load) of the curves were plotted with the wire length and the following graph is obtained. If the Young's modulus of given steel wires is x × 1011N m−2 , then the value of x is _____ .

Q23.The pressure P1 and density d1 of diatomic gas (γ = 75 ) changes suddenly to P2(> P1) and d2 respectively during an adiabatic process. The temperature of the gas increases and becomes____times of its initial temperature. (given d2 = 32) d1

Q23.In a carnot engine, the temperature of reservoir is 527°C and that of sink is 200 K . If the workdone by the engine when it transfers heat from reservoir to sink is 12000 kJ , the quantity of heat absorbed by the engine from reservoir is _____ ×106 J.

Q23.A uniform heavy rod of mass 20 kg. Cross sectional area 0 . 4 m2 and length 20 m is hanging from a fixed support. Neglecting the lateral contraction, the elongation in the rod due to its own weight is 𝑥× 10-9 m. The value of 𝑥 is _____ . (Given. Young's modulus 𝑌= 2 × 1011Nm-2 and 𝑔= 10 m s-2 )

Q24.Two waves executing simple harmonic motion travelling in the same direction with same amplitude and frequency are superimposed. The resultant amplitude is equal to the √3 times of amplitude of individual motions. The phase difference between the two motions is _____ (degree)

Q24.Moment of Inertia (M.I.) of four bodies having same mass 𝑀 and radius 2𝑅 are as follows 𝐼1 = M.I. of solid sphere about its diameter 𝐼2 = M.I. of solid cylinder about its axis 𝐼3 = M.I. of solid circular disc about its diameter 𝐼4 = M.I. of thin circular ring about its diameter If 2𝐼2 + 𝐼3 + 𝐼4 = 𝑥𝐼1 then the value of 𝑥 will be _____ .

Q24.A unit scale is to be prepared whose length does not change with temperature and remains 20 cm, using a bimetallic strip made of brass and iron each of different length. The length of both components would change in such a way that difference between their lengths remains constant. If length of brass is 40 cm and length of iron will be _____ cm. 𝛼iron = 1 . 2 × 10-5 K-1 and 𝛼brass = 1 . 8 × 10-5 K-1.

Q24.Two coils require 20 minutes and 60 minutes respectively to produce same amount of heat energy when connected separately to the same source. If they are connected in parallel arrangement to the same source; the time required to produce same amount of heat by the combination of coils, will be _____ min.

Q24.The elastic behaviour of material for linear stress and linear strain, is shown in the figure. The energy density for a linear strain of 5 × 10−4 is _____ kJ m−3 . Assume that material is elastic upto the linear strain of 5 × 10−4 , JEE Main 2022 (26 Jun Shift 1) JEE Main Previous Year Paper

Q24.As per given figures, two springs of spring constants 𝐾 and 2 K are connected to mass m. If the period of oscillation in figure (a) is 3 s, then the period of oscillation in figure (b) will be √𝑥 s. The value of 𝑥 is _____ .

Q24.A geyser heats water flowing at a rate of 2. 0 kg per minute from 30°C to 70°C . If geyser operates on a gas burner, the rate of combustion of fuel will be _____ g min−1 . JEE Main 2022 (26 Jun Shift 2) JEE Main Previous Year Paper [Heat of combustion = 8 × 103 Jg−1 , Specific heat of water = 4. 2 Jg−1 ∘C−1 ]

Q24.A string of area of cross-section 4 mm2 and length 0. 5 is connected with a rigid body of mass 2 kg. The body is rotated in a vertical circular path of radius 0. 5 m. The body acquires a speed of 5 m s−1 at the bottom of the circular path. Strain produced in the string when the body is at the bottom of the circle is _____ ×10−5 . (Use Young's modulus 1011 N m−2 and g = 10 m s−2 )

Q24.The position vector of 1 kg object is →r= (3ˆi −ˆj) m and its velocity →v= (3ˆj ˆk) its angular momentum is √x N m s, where x is

Q24.A capacitor of capacitance 50 pF is charged by 100 V source. It is then connected to another uncharged identical capacitor. Electrostatic energy loss in the process is____ nJ .

Q24.The diameter of an air bubble which was initially 2 mm, rises steadily through a solution of density $1750 \mathrm{~kg} / \mathrm{m}^3$ at the rate of $0.35 \mathrm{~cm} / \mathrm{s}$. Coefficient of viscosity of the solution is ______ (Assume mass of the bubble to be negligible) (Answer in Poise to the nearest integer)

Q24.A particle executes simple harmonic motion. Its amplitude is 8 cm and time period is 6 s. The time it will take to travel from its position of maximum displacement to the point corresponding to half of its amplitude, is _____ s

Q24.The displacement current of 4. 425 μA is developed in the space between the plates of parallel plate capacitor when voltage is changing at a rate of 106 V s−1 . The area of each plate of the capacitor is 40 cm2 . The distance between each plate of the capacitor is x × 10−3 m . The value of x is , (Permittivity of free space, ε0 = 8. 85 × 10−12 C2 N−1 m−2 ) _______

Q24.One mole of a monoatomic gas is mixed with three moles of a diatomic gas. The molecular specific heat of mixture at constant volume is α2 R J mol K−1 ; then the value of α will be _____ . (Assume that the given 4 diatomic gas has no vibrational mode.)

Q24.A spherical soap bubble of radius 3 cm is formed inside another spherical soap bubble of radius 6 cm. If the internal pressure of the smaller bubble of radius 3 cm in the above system is equal to the internal pressure of the another single soap bubble of radius r cm. The value of r is _____

Q24.A tunning fork of frequency 340 Hz resonates in the fundamental mode with an air column of length 125 cm in a cylindrical tube closed at one end. When water is slowly poured in it, the minimum height of water required for observing resonance once again is _____ cm. (Velocity of sound in air is 340 ms−1 )

Q24.A mass 0. 9 kg, attached to a horizontal spring, executes SHM with an amplitude A1 . When this mass passes through its mean position, then a smaller mass of 124 g is placed over it and both masses move together with amplitude A2 . If the ratio A2A1 is α−1α , then the value of α will be _____ .

Q24.When a car is approaching the observer, the frequency of horn is 100 Hz. After passing the observer, it is 50 Hz. If the observer moves with the car, the frequency will be x3 Hz where x =_____ .

Q25.The frequency of echo will be _____ Hz if the train blowing a whistle of frequency 320 Hz is moving with a velocity of 36 km h-1 towards a hill from which an echo is heard by the train driver. Velocity of sound in air JEE Main 2022 (28 Jul Shift 1) JEE Main Previous Year Paper is 330 m s-1.

Q25.The metallic bob of simple pendulum has the relative density 5. The time period of this pendulum is 10 s. If the metallic bob is immersed in water, then the new time period becomes 5√𝑥 s. The value of 𝑥 will be _____ .