Practice Questions

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 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.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 _____.

Q11.A parallel plate capacitor of capacitance 2 F is charged to a potential 𝑉. The energy stored in the capacitor is 𝐸1. The capacitor is now connected to another uncharged identical capacitor in parallel combination. The 𝐸2 energy stored in the combination is 𝐸2. The ratio is 𝐸1 (1) 2: 1 (2) 2: 3 (3) 1: 2 (4) 1: 4

Q11.As shown in the figure, a network of resistors is connected to a battery of 24 V with an internal resistance of 3 𝛺. The currents through the resistors 𝑅4 and 𝑅5 are 𝐼4 and 𝐼5 respectively. The values of 𝐼4 and 𝐼5 are: 8 2 24 6 (1) 𝐼4 = 5 A and I5 = 5 A (2) 𝐼4 = 5 A and 𝐼5 = 5 A (3) 𝐼4 = 6 A and 𝐼5 = 24 A (4) 𝐼4 = 2 A and 𝐼5 = 8 A 5 5 5 5

Q11.A metal block of base area 0. 20 m2 is placed on a table, as shown in figure. A liquid film of thickness 0. 25 mm is inserted between the block and the table. The block is pushed by a horizontal force of 0. 1 N and moves with a constant speed. If the viscosity of the liquid is 5. 0 × 10–3 Pl, the speed of block is ______ ×10−3 m s−1 .

Q11.A spherical ball of radius 1 mm and density 10. 5 g cc−1 is dropped in glycerine of coefficient of viscosity 9. 8 poise and density 1. 5 g cc−1 . Viscous force on the ball when it attains constant velocity is 3696 × 10−x N . The value of x is (Given, g = 9. 8 m s−2 and π = 227 )

Q11.The surface of water in a water tank of cross section area 750 cm2 on the top of a house is h m. above the tap level. The speed of water coming out through the tap of cross section area 500 mm2 is 30 cm s−1 . At that instant, dh is x × 10−3 m s−1 . The value of x will be ______. dt

Q12.In an Isothermal change, the change in pressure and volume of a gas can be represented for three different temperature; T3 > T2 > T1 as: JEE Main 2023 (24 Jan Shift 2) JEE Main Previous Year Paper (1) (2) (3) (4)

Q12.An air bubble of diameter 6 mm rises steadily through a solution of density 1750 kg m−3 at the rate of 0. 35 cm s−1 . The co-efficient of viscosity of the solution (neglect density of air) is ________ Pas (given, g = 10 m s−2 ).

Q13.A circular loop of radius 𝑅 is carrying current 𝑖 A. The ratio of magnetic field at the centre of circular loop and at a distance 𝑅 from the center of the loop on its axis is : (1) 1: 3√2 (2) 3√2: 2 (3) 2√2: 1 (4) 1: √2 JEE Main 2023 (24 Jan Shift 1) JEE Main Previous Year Paper 10

Q13.Two simple harmonic waves having equal amplitudes of 8 cm and equal frequency of 10 Hz are moving along the same direction. The resultant amplitude is also 8 cm. The phase difference between the individual waves is _____ degree.

Q13.A simple pendulum with length 100 cm and bob of mass 250 g is executing S.H.M of amplitude 10 cm. The maximum tension in the string is found to be x N . The value of x is _____. 40

Q14.A particle of mass 250 g executes a simple harmonic motion under a periodic force F = (–25x) N. The particle attains a maximum speed of 4 m s−1 during its oscillation. The amplitude of the motion is ______ cm.

Q14.The distance between two consecutive points with phase difference of 60° in a wave of frequency 500 Hz is 6. 0 m . The velocity with which wave is travelling is ______ km s−1 .

Q14.At a given point of time the value of displacement of a simple harmonic oscillator is given as y = A cos(30°). If amplitude is 40 cm and kinetic energy at that time is 200 J, the value of force constant 1. 0 × 10x N m–1 . The value of x is _____.

Q14.A conducting loop of radius cm is placed perpendicular to a uniform magnetic field of 0 . 5 T. The √𝜋 magnetic field is decreased to zero in 0 . 5 s at a steady rate. The induced emf in the circular loop at 0 . 25 s is: (1) emf = 1mV (2) emf = 10mV (3) emf = 100mV (4) emf = 5mV

Q14.The displacement equations of two interfering waves are given by y1 = 10 sin (ωt + π3 ) cm, cm respectively. The amplitude of the resultant wave is _____ cm. y2 = 5[sin (ωt) + √3 cos ωt]

Q14.A guitar string of length 90 cm vibrates with a fundamental frequency of 120 Hz. The length of the string producing a fundamental of 180 Hz will be _____ cm

Q14.The velocity of a particle executing SHM varies with displacement ( x) as 4v2 = 50–x2 . The time period of oscillations is x 7 s. The value of x is ______. [Take π = 227 ]

Q15.If →𝐸 and →𝐾 represent electric field and propagation vectors of the EM waves in vacuum, then magnetic field vector is given by: (𝜔- angular frequency) 1 → → → → (1) 𝐾× 𝐸 (2) 𝜔𝐸× 𝐾 𝜔 (3) 𝜔→𝐾× →𝐸 (4) →𝐾× →𝐸

Q15.A uniform electric field of 10 N C−1 is created between two parallel charged plates (as shown in figure). An electron enters the field symmetrically between the plates with a kinetic energy 0. 5 eV. The length of each plate is 10 cm. The angle (θ) of deviation of the path of electron as it comes out of the field is ______(in degree). JEE Main 2023 (25 Jan Shift 1) JEE Main Previous Year Paper

Q15.A cubical volume is bounded by the surfaces x = 0, x = a, y = 0, y = a, z = 0, z = a . The electric field in → the region is given by E = E0xˆi. Where E0 = 4 × 104 NC−1 m−1 . If a = 2 cm , the charge contained in the cubical volume is Q × 10–14 C . The value of Q is ______. (Take ϵ0 = 9 × 10−12 C2 N−1m−2 )

Q15.The electric potential at the centre of two concentric half rings of radii R1 and R2 , having same linear charge density λ is . (1) 2λ (2) λ ∈0 2∈0 (3) λ (4) λ 4∈0 ∈0

Q16.A 600 pF capacitor is charged by 200 V supply. It is then disconnected from the supply and is connected to another uncharged 600 pF capacitor. Electrostatic energy lost in the process is _____ μJ.