Practice Questions

Q23.A capacitor of capacitance 150. 0 μF is connected to an alternating source of emf given by E = 36 sin(120πt) V. The maximum value of current in the circuit is approximately equal to: (1) 2 A (2) √2 A (3) 2√2 A (4) 1 A √2 → →

Q23.A wire of length 1 m moving with velocity 8 m s−1 at right angles to a magnetic field of 2 T. The magnitude of induced emf, between the ends of wire will be ___________. (1) 20 V (2) 8 V (3) 12 V (4) 16 V

Q23.A vessel of depth d is half filled with oil of refractive index n1 and the other half is filled with water of refractive index n2. The apparent depth of this vessel when viewed from above will be- (1) 2d(n1+n2) (2) d(n1+n2) n1+n2 2n1n2 (3) dn1n2 (4) dn1n2 2(n1+n2) (n1+n2)

Q23.Figure below shows a liquid being pushed out of the tube by a piston having area of cross section 2 . 0 cm2. The area of cross section at the outlet is 10 mm2. If the piston is pushed at a speed of 4 cm s-1, the speed of outgoing fluid is _____ cm s-1

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.When a beam of white light is allowed to pass through convex lens parallel to principal axis, the different colours of light converge at different point on the principle axis after refraction. This is called : (1) Scattering (2) Chromatic aberration (3) Spherical aberration (4) Polarisation

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.

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 energy density associated with electric field E and magnetic field B of an electromagnetic wave in free space is given by ( ε0− permittivity of free space, μ0− permeability of free space) (1) UE = 2ε0E2 , UB = 2μ0 B2 (2) UE = ε0E22 , UB = 2μ0B2 μ0B2 , UB = 2 (3) UE = ε0E22 , UB = μ0B22 (4) UE = 2ε0E2

Q24.In a reflecting telescope, a secondary mirror is used to: (1) reduce the problem of mechanical support (2) make chromatic aberration zero (3) move the eyepiece outside the telescopic tube (4) remove spherical aberration

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.The width of fringe is 2 mm on the screen in a double slit experiment for the light of wavelength of 400 nm. The width of the fringe for the light of wavelength 600 nm will be: (1) 4 mm (2) 2 mm (3) 1. 33 mm (4) 3 mm

Q25.When one light ray is reflected from a plane mirror with 30° angle of reflection, the angle of deviation of the ray after reflection is: JEE Main 2023 (11 Apr Shift 2) JEE Main Previous Year Paper (1) 120° (2) 110° (3) 140° (4) 130°

Q25.The difference between threshold wavelengths for two metal surfaces A and B having work function ϕA = 9 eV and ϕB = 4. 5 eV in nm is: {Given, hc = 1242 eV nm } (1) 540 (2) 276 (3) 264 (4) 138

Q25.The threshold wavelength for photoelectric emission from a material is 5500 A . Photoelectrons will be emitted, when this material is illuminated with monochromatic radiation from a A. 75 W infra-red lamp B. 10 W infra-red lamp C. 75 W ultra-violet lamp D. 10 W ultra-violet lamp Choose the correct answer from the options given below : (1) B and C only (2) A and D only (3) C only (4) C and D only

Q25.Match List I and List II → → A Gauss’s Law in Electrostatics I ∮ E ⋅ dl = −dϕBdt → → B Faraday's Law II ∮ B ⋅d A = 0 → → C Gauss’s Law in Magnetism III ∮ B ⋅d l = μ0ic + μ0 ∈0 dϕEdt q D Ampere-Maxwell Law IV ∮→E ⋅d→s= ∈0 Choose the correct answer from the options given below : (1) A-IV, B-I, C-II, D-III (2) A-I, B-II, C-III, D-IV (3) A-III, B-IV, C-I, D-II (4) A-II, B-III, C-IV, D-I JEE Main 2023 (25 Jan Shift 2) JEE Main Previous Year Paper

Q26.Electron beam used in an electron microscope, when accelerated by a voltage of 20 kV has a de-Broglie wavelength of λ0 . If the voltage is increased to 40 kV then the de-Broglie wavelength associated with the electron beam would be: (1) 3λ0 (2) 9λ0 (3) λ0 (4) λ0 2 √2

Q26.Proton (P) and electron (e) will have same de-Broglie wavelength when the ratio of their momentum is (assume, mp = 1849 me ) (1) 1 : 1 (2) 1 : 1849 (3) 1 : 43 (4) 43 : 1

Q26.If a radioactive element having half-life of 30 min is undergoing beta decay, the fraction of radioactive element remains undecayed after 90 min will be : (1) 1 (2) 1 8 16 (3) 1 (4) 1 4 2

Q26.The light rays from an object have been reflected towards an observer from a standard flat mirror, the image observed by the observer are :- A. Real B. Erect C. Smaller in size than object D. Laterally inverted Choose the most appropriate answer from the options given below: (1) B and D only (2) B and C only (3) A and D only (4) A, C and D only

Q26.In an experiment to find emf of a cell using potentiometer, the length of null point for a cell of emf 1 . 5 V is found to be 60 cm. If this cell is replaced by another cell of emf 𝐸. the length-of null point increases by 𝑥 40 cm. The value of 𝐸 is V. The value of 𝑥 is ______. 10

Q27.An electron of a hydrogen like atom, having Z = 4 , jumps from 4th energy state to 2nd energy state, The energy released in this process, will be: (Given Rch = 13. 6 eV ) Where R = Rydberg constant c = Speed of light in vacuum h = Planck's constant (1) 13. 6 eV (2) 10. 5 eV (3) 3. 4 eV (4) 40. 8 eV

Q27.The radius of electron's second stationary orbit in Bohr's atom is R. The radius of 3rd orbit will be (1) R (2) 2. 25 R 3 (3) 3R (4) 9R

Q27.The current required to be passed through a solenoid of 15 cm length and 60 turns in order to demagnetise a bar magnet of magnetic intensity 2 . 4 × 103 A m – 1 is ________ A.

Q28.The ratio of the density of oxygen nucleus (168O) and helium nucleus (42He) is (1) 4 : 1 (2) 8 : 1 (3) 1 : 1 (4) 2 : 1