Practice Questions

Q23.The velocity of a small ball of mass 0 . 3 g and density 8 g cc-1 when dropped in a container filled with glycerine becomes constant after some time. If the density of glycerine is 1 . 3 g cc-1, then the value of viscous force acting on the ball will be 𝑥× 10-4 N, the value of 𝑥 is _____ . [use 𝑔= 10 m s-2]

Q23.In an experiment to determine the velocity of sound in air at room temperature using a resonance tube, the first resonance is observed when the air column has a length of 20. 0 cm for a tuning fork of frequency 400 Hz is used. The velocity of the sound at room temperature is 336 m s−1 . The third resonance is observed when the air column has a length of _____ cm

Q23.A wire of length 𝐿 and radius 𝑟 is clamped rigidly at one end. When the other end of the wire is pulled by a force 𝐹, its length increases by 5 cm. Another wire of the same material of length 4 L and radius 4𝑟 is pulled by a force 4 𝐹 under same conditions. The increase in length of this wire is _____ cm.

Q23.A disc of mass 1 kg and radius R is free of rotate about a horizontal axis passing through its centre and perpendicular to the plane of disc. A body of same mass as that of disc is fixed at the highest point of the disc. Now the system is released, when the body comes to the lowest position, its angular speed will be 4√x3R rad s−1 where x = _____ .

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 diatomic gas (γ = 1. 4) does 400 J of work when it is expanded isobarically. The heat given to the gas in the process is _____ J.

Q23.A 0 . 5 kg block moving at a speed of 12 ms-1 compresses a spring through a distance 30 cm when its speed is halved. The spring constant of the spring will be _____ Nm-1 JEE Main 2022 (25 Jun Shift 1) JEE Main Previous Year Paper

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.A metre scale is balanced on a knife edge at its centre. When two coins, each of mass 10 g are put one on the top of the other at the 10. 0 cm mark the scale is found to be balanced at 40. 0 cm mark. The mass of the metre scale is found to be x × 10−2 kg. The value of x is _____ . Q24. 0. 056 kg of Nitrogen is enclosed in a vessel at a temperature of 127°C. The amount of heat required to double the speed of its molecules is_____ kcal. (Take R = 2 cal mole −1 K−1 )

Q23.A block of mass 200 g is kept stationary on a smooth inclined plane by applying a minimum horizontal force 𝐹= √𝑥 N as shown in figure. JEE Main 2022 (25 Jun Shift 2) JEE Main Previous Year Paper The value of 𝑥= _____.

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 )

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 distance of centre of mass from end A of a one dimensional rod (AB) having mass density ρ = kg m−1 and length L (in meter) is 3Lα m. The value of α is _____ (where x is the distance ρ0(1 −x2L2 ) form end A ) JEE Main 2022 (28 Jul Shift 2) JEE Main Previous Year Paper

Q23.The elongation of a wire on the surface of the earth is 10−4 m. The same wire of same dimensions is elongated by 6 × 10−5 m on another planet. The acceleration due to gravity on the planet will be _____ m s−2 . (Take acceleration due to gravity on the surface of earth = 10 m s−2 )

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 =_____ .

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 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.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.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.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 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 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.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.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 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.