Practice Questions

Q28.A 20 cm long metallic rod is rotated with 210 rpm about an axis normal to the rod passing through its one end. The other end of the rod is in contact with a circular metallic ring. A constant and uniform magnetic field 0. 2 T parallel to the axis exists everywhere. The emf developed between the centre and the ring is _________ mV. JEE Main 2023 (15 Apr Shift 1) JEE Main Previous Year Paper (Take π = 227 )

Q28.A nucleus with mass number 242 and binding energy per nucleon as 7. 6 MeV breaks into two fragment each with mass number 121. If each fragment nucleus has binding energy per nucleon as 8. 1 MeV, the total gain in binding energy is _______ MeV.

Q28.A common example of alpha decay is 23892U →23490 Th +2 He4 + Q Given: 23892U = 238. 05060 u 23490Th = 234. 04360 u 42He = 4. 00260 u and 1u = 931. 5 MeVc2 The energy released (Q) during the alpha decay of 23892U is _____ MeV.

Q28.Nucleus a having Z = 17 and equal number of protons and neutrons has 1. 2 MeV binding energy per nucleon. Another nucleus B of Z = 12 has total 26 nucleons and 1. 8 MeV binding energy per nucleons. The JEE Main 2023 (01 Feb Shift 2) JEE Main Previous Year Paper difference of binding energy of B and A will be ______ MeV.

Q28.Given below are two statements : Statement I : Stopping potential in photoelectric effect does not depend on the power of the light source. Statement II : For a given metal, the maximum kinetic energy of the photoelectron depends on the wavelength of the incident light. In the light of above statements, choose the most appropriate answer from the options given below. (1) Statement I is incorrect but statement II is correct (2) Both Statement I and Statement II are incorrect (3) Statement I is correct but statement II is incorrect (4) Both statement I and statement II are correct

Q28.A radio active material is reduced to 1 of its original amount in 3 days. If 8 × 10−3 kg of the material is left 8 after 5 days the initial amount of the material is (1) 40 g (2) 32 g (3) 64 g (4) 256 g

Q28.A series LCR circuit is connected to an ac source of 220 V, 50 Hz. The circuit contain a resistance 𝑅= 100 Ω and an inductor of inductive reactance 𝑋𝐿= 79 . 6 Ω. The capacitance of the capacitor needed to maximize the average rate at which energy is supplied will be ______ μF.

Q28.In Young’s double slit experiment, two slits 𝑆1 and 𝑆2 are 𝑑 distance apart and the separation from slits to screen is 𝐷 (as shown in figure). Now if two transparent slabs of equal thickness 0 . 1 mm but refractive index 1 . 51 and 1 . 55 are introduced in the path of beam λ = 4000 Å from 𝑆1 and 𝑆2 respectively. The central bright fringe spot will shift by ________ number of fringes.

Q28.A radioactive nucleus decays by two different process. The half life of the first process is 5 minutes and that of the second process is 30 s. The effective half-life of the nucleus is calculated to be 11α s. The value of α is ______.

Q28.In the circuit shown in the figure, the ratio of the quality factor and the band width is _____ s.

Q28.A 1 m long metal rod 𝑋𝑌 completes the circuit as shown in figure. The plane of the circuit is perpendicular to the magnetic field of flux density 0 . 15 T. If the resistance of the circuit is 5 Ω, the force needed to move the rod in direction, as indicated, with a constant speed of 4 m s-1 will be _______10 – 3 N.

Q28.An insulated copper wire of 100 turns is wrapped around a wooden cylindrical core of the cross-sectional area 24 cm2. The two ends of the wire are connected to a resistor. The total resistance in the circuit is 12 Ω. If an externally applied uniform magnetic field in the core along its axis changes from 1 . 5 T in one direction to 1 . 5 T in the opposite direction, the charge flowing through a point in the circuit during the change of magnetic field will be _____ mC.

Q28.If the binding energy of ground state electron in a hydrogen atom is 13. 6 eV , then, the energy required to remove the electron from the second excited state of Li 2+ will be: x × 10−1 eV . The value of x is _____.

Q29.The energy levels of an atom is shown is figure. Which one of these transitions will result in the emission of a photon of wavelength 124. 1 nm? Given ( h = 6. 62 × 10–34 J s) JEE Main 2023 (25 Jan Shift 2) JEE Main Previous Year Paper (1) B (2) A (3) C (4) D

Q29.From the given transfer characteristic of a transistor in CE configuration, the value of power gain of this configuration is 10x , for RB = 10 kΩ, and RC = 1 kΩ. The value of x is _____. JEE Main 2023 (13 Apr Shift 1) JEE Main Previous Year Paper

Q29.For the logic circuit shown, the output waveform at Y is (1) (2) (3) (4)

Q29.A bi convex lens of focal length 10 cm is cut in two identical parts along a plane perpendicular to the principal axis. The power of each lens after cut is _____ D.

Q29.For a given transistor amplifier circuit in CE configuration VCC = 1 V, RC = 1 kΩ, Rb = 100 kΩ and β = 100 . Value of base current Ib is JEE Main 2023 (08 Apr Shift 2) JEE Main Previous Year Paper (1) Ib = 1. 0 μA (2) Ib = 0. 1 μA (3) Ib = 100 μA (4) Ib = 10 μA

Q29.Given below are two statements: Statement I : In a typical transistor, all three regions emitter, base and collector have same doping level. Statement II : in a transistor, collector is the thickest and base is the thinnest segment. In the light of the above statements, choose the most appropriate answer from the options given below. (1) Both Statement I and Statement II are correct (2) Both Statement I and Statement II are incorrect (3) Statement I is incorrect but Statement II is (4) Statement I is correct but Statement II is correct incorrect

Q29.Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R Assertion A: Diffusion current in a p −n junction is greater than the drift current in magnitude if the junction is forward biased. Reason R: Diffusion current in a p −n junction is form the n-side to the p-side if the junction is forward biased. In the light of the above statements, choose the most appropriate answer from the options given below. (1) Both A and R are correct but R is NOT the (2) A is correct but R is not correct correct explanation of A (3) A is not correct but R is correct (4) Both A and R is correct and R is the correct explanation of A

Q29.In a medium the speed of light wave decreases to 0 . 2 times to its speed in free space. The ratio of relative permittivity to the refractive index of the medium is 𝑥: 1. The value of 𝑥 is ______. (Given speed of light in free space = 3 × 108 m s-1 and for the given medium 𝜇𝑟= 1)

Q29.A point source of light is placed at the centre of curvature of a hemispherical surface. The source emits a power of 24 W. The radius of curvature of hemisphere is 10 cm and the inner surface is completely reflecting. The force on the hemisphere due to the light falling on it is ______ × 10-8 N.

Q29.The radius of curvature of each surface of a convex lens having refractive index 1 . 8 is 20 cm. The lens is now immersed in a liquid of refractive index 1 . 5. The ratio of power of lens in air to its power in the liquid will be 𝑥: 1. The value of 𝑥 is

Q29.The output Y for the inputs A and B of circuit is given by Truth table of the shown circuit is : (1) A B Y (2) A B Y ⎡ 0 0 1 ⎤ ⎡ 0 0 1 ⎤ 0 1 1 0 1 0 1 0 1 1 0 0 1 1 0 1 1 1 ⎣ ⎦ ⎣ ⎦ (3) A B Y (4) A B Y ⎡ 0 0 0 ⎤ ⎡ 0 0 0 ⎤ 0 1 1 0 1 1 1 0 1 1 0 1 1 1 1 1 1 0 ⎣ ⎦ ⎣ ⎦

Q29.The logic gate equivalent to the given circuit diagram is : JEE Main 2023 (24 Jan Shift 2) JEE Main Previous Year Paper (1) OR (2) NAND (3) NOR (4) AND