Practice Questions

Q24.A fish rising vertically upward with a uniform velocity of 8 m s–1, observes that a bird is diving vertically downward towards the fish with the velocity of 12 m s–1. If the refractive index of water is 34 , then the actual velocity of the diving bird to pick the fish, will be __________m s−1.

Q24.In an experiment with sonometer when a mass of 180 g is attached to the string, it vibrates with fundamental frequency of 30 Hz. When a mass 𝑚 is attached, the string vibrates with fundamental frequency of 50 Hz. The value of 𝑚 is ______ g.

Q24.The fundamental frequency of vibration of a string between two rigid support is 50 Hz. The mass of the string is 18 g and its linear mass density is 20 g m−1 . The speed of the transverse waves so produced in the string is _______ m s–1 .

Q24.A hole is drilled in a metal sheet. At 27 °C, the diameter of hole is 5 cm. When the sheet is heated to 177 °C, the change in the diameter of hole is 𝑑× 10-3 cm . The value of 𝑑 will be _____, if coefficient of linear expansion of the metal is 1 . 6 × 10-5 / ∘C

Q24.The amplitude of a particle executing SHM is 3 cm. The displacement at which its kinetic energy will be 25% more than the potential energy is: ______ cm.

Q24.A steel rod has a radius of 20 mm and a length of 2 . 0 m . A force of 62 . 8 kN stretches it along its length. Young's modulus of steel is 2 . 0 × 1011N m-2. The longitudinal strain produced in the wire is _________ × 10-5. JEE Main 2023 (06 Apr Shift 1) JEE Main Previous Year Paper

Q24.Two transparent media having refractive indices 1. 0 and 1. 5 are separated by a spherical refracting surface of radius of curvature 30 cm. The centre of curvature of surface is towards denser medium and a point object is placed on the principal axis in rarer medium at a distance of 15 cm from the pole of the surface. The distance of image from the pole of the surface is cm.

Q24.A transverse harmonic wave on a string is given by 𝑦𝑥, 𝑡= 5 sin6𝑡+ 0 . 003𝑥 where 𝑥 and 𝑦 are in cm and 𝑡 in sec. The wave velocity is _________ m s-1.

Q25.Two equal positive point charges are separated by a distance 2𝑎. The distance of a point from the centre of the line joining two charges on the equatorial line (perpendicular bisector) at which force experienced by a test charge becomes maximum is 𝑎 The value of 𝑥 is ______. 𝑞0 √𝑥. JEE Main 2023 (01 Feb Shift 1) JEE Main Previous Year Paper

Q25.The equation of wave is given by 𝑌= 10-2sin2𝜋160𝑡- 0 . 5𝑥+ 4, where 𝑥 and 𝑌 are in 𝑚 and 𝑡 in 𝑠. The speed of the wave is _______ km h-1.

Q25.A block of mass 2 kg is attached with two identical springs of spring constant 20 N m-1 each. The block is placed on a frictionless surface and the ends of the springs are attached to rigid supports (see figure). When the mass is displaced from its equilibrium position, it executes a simple harmonic motion. The time period of oscillation is 𝜋 in SI unit. The value of 𝑋 is______. √𝑋 JEE Main 2023 (24 Jan Shift 1) JEE Main Previous Year Paper 𝑞

Q25.In the following circuit, the magnitude of current 𝐼1, is ______ A. JEE Main 2023 (30 Jan Shift 1) JEE Main Previous Year Paper - 1 A s-1, then the value of 𝑉AB at this instant will be ______ V.

Q25.Three concentric spherical metallic shells 𝑋, 𝑌 and 𝑍 of radius 𝑎, 𝑏 and 𝑐 respectively 𝑎< 𝑏< 𝑐 have surface charge densities 𝜎, – 𝜎 and 𝜎, respectively. The shells 𝑋 and 𝑍 are at same potential. If the radii of 𝑋 & 𝑌 are 2 cm and 3 cm, respectively. The radius of shell 𝑍 is _____cm. Q26.10 resistors each of resistance 10 Ω can be connected in such as to get maximum and minimum equivalent resistance. The ratio of maximum and minimum equivalent resistance will be________.

Q25.In the given figure the total charge stored in the combination of capacitors is 100 µC. The value of ‘ x’ is ______________.

Q25.An electron revolves around an infinite cylindrical wire having uniform linear charge density 2 × 10-8 C m-1 in circular path under the influence of attractive electrostatic field as shown in the figure. The velocity of electron with which it is revolving is ______________ × 106 m s-1. Given mass of electron = 9 × 10-31 kg

Q25.Two convex lenses of focal length 20 cm each are placed coaxially with a separation of 60 cm between them. The image of the distant object formed by the combination is at _____ cm from the first lens.

Q25.Two light waves of wavelengths 800 and 600 nm are used in Young's double slit experiment to obtain interference fringes on a screen placed 7 m away from plane of slits. If the two slits are separated by 0. 35 mm , then shortest distance from the central bright maximum to the point where the bright fringes of the two wavelength coincide will be ______ mm.

Q25.In the figure given below. a block of mass 𝑀= 490 g placed on a frictionless table is connected with two springs having same spring constant (𝐾= 2 N m-1). If the block is horizontally displaced through 𝑋 m then the number of complete oscillations it will make in 14𝜋 seconds will be ______.

Q25.A person driving car at a constant speed of 15 m s-1 is approaching a vertical wall. The person notices a change of 40 Hz in the frequency of his car’s horn upon reflection from the wall. The frequency of horn is _______Hz . (Given: Speed of sound: 30 m s-1)

Q25.Two vertical parallel mirrors A and B are separated by 10 cm. A point object O is placed at a distance of 2 cm from mirror A. The distance of the second nearest image behind mirror A from the mirror A is _______ cm.

Q25.As shown in the figure, in Young's double slit experiment, a thin plate of thickness t = 10 μm and refractive index μ = 1. 2 is inserted infront of slit S1 . The experiment is conducted in air ( μ = 1 ) and uses a monochromatic light of wavelength λ = 500 nm. Due to the insertion of the plate, central maxima is shifted by a distance of xβ0 . β0 is the fringe-width before the insertion of the plate. The value of the x is ______.

Q25.A convex lens of refractive index 1. 5 and focal length 18 cm in air is immersed in water. The change in focal length of the lens will be_____ cm. (Given refractive index of water = 43 )

Q25.Three point charges 𝑞, - 2𝑞 and 2𝑞 are placed on 𝑥 axis at a distance 𝑥= 0, 𝑥= 3 and 𝑥= 𝑅 respectively 4𝑅 from origin as shown. If 𝑞= 2 × 10-6 C and 𝑅= 2 cm, the magnitude of net force experienced by the charge -2𝑞 is _____ N.

Q25.Unpolarised light is incident on the boundary between two dielectric media, whose dielectric constants are 2. 8 (medium – 1) and 6. 8 (medium – 2), respectively. To satisfy the condition, so that the reflected and refracted 1 rays are perpendicular to each other, the angle of incidence should be tan−1 (1 + 10θ ) 2 , the value of θ is ______. (Given for dielectric media, μr = 1 )

Q26.A rectangular parallelopiped is measured as 1 cm × 1 cm × 100 cm. If its specific resistance is 3 × 10-7Ω m, then the resistance between its two opposite rectangular faces will be _____ × 10-7Ω.