Practice Questions

Q29.Two immiscible liquids of refractive indices 8 and 3 respectively are put in a beaker as shown in the figure. 5 2 The height of each column is 6 cm . A coin is placed at the bottom of the beaker. For near normal vision, the apparent depth of the coin is α 4 cm . The value of α is _______.

Q29.In Young's double slit experiment, monochromatic light of wavelength 5000 A is used. The slits are 1 . 0 mm apart and screen is placed at 1 . 0 m away from slits. The distance from the centre of the screen where intensity becomes half of the maximum intensity for the first time is ______ × 10-6 m .

Q29.A power transmission line feeds input power at 2 . 3 kV to a step down transformer with its primary winding having 3000 turns. The output power is delivered at 230 V by the transformer. The current in the primary of the transformer is 5 A and its efficiency is 90%. The winding of transformer is made of copper. The output current of transformer is ____A.

Q29.In a single slit diffraction pattern, a light of wavelength 6000 A is used. The distance between the first and third minima in the diffraction pattern is found to be 3 mm when the screen is placed 50 cm away from slits. The width of the slit is ____ ×10−4 m .

Q29.The distance between object and its 3 times magnified virtual image as produced by a convex lens is 20 cm . The focal length of the lens used is ________ cm .

Q29.A parallel beam of monochromatic light of wavelength 600 nm passes through single slit of 0.4 mm width. Angular divergence corresponding to second order minima would be ______ ×10−3rad.

Q29.In a single slit experiment, a parallel beam of green light of wavelength 550 nm passes through a slit of width 0.20 mm. The transmitted light is collected on a screen 100 cm away. The distance of first order minima from the central maximum will be x × 10−5 m . The value of x is : JEE Main 2024 (05 Apr Shift 2) JEE Main Previous Year Paper

Q29.A parallel beam of monochromatic light of wavelength 5000 A is incident normally on a single narrow slit of width 0 . 001 mm. The light is focused by convex lens on screen, placed on its focal plane. The first minima will be formed for the angle of diffraction of ______ (degree). 𝛼

Q29.In Young's double slit experiment, carried out with light of wavelength 5000\AA, the distance between the slits is 0.3 mm and the screen is at 200 cm from the slits. The central maximum is at x = 0 cm . The value of x for third maxima is _____ mm .

Q29.Two wavelengths λ1 and λ2 are used in Young's double slit experiment. λ1 = 450 nm and λ2 = 650 nm. The minimum order of fringe produced by λ2 which overlaps with the fringe produced by λ1 is n. The value of n is _____.

Q30.In an alpha particle scattering experiment distance of closest approach for the α particle is 4.5 × 10−14 m . If target nucleus has atomic number 80 , then maximum velocity of α - particle is _______ ×105 m/s approximately. = 9 × 109 SI unit, mass of α particle = 6.72 × 10−27 kg) ( 4πϵ01

Q30.Monochromatic light of wavelength 500 nm is used in Young's double slit experiment. An interference pattern is obtained on a screen. When one of the slits is covered with a very thin glass plate (refractive index = 1.5 ), the central maximum is shifted to a position previously occupied by the 4th bright fringe. The thickness of the glass-plate is ______ μm .

Q30.In Franck-Hertz experiment, the first dip in the current-voltage graph for hydrogen is observed at 10.2 V. The wavelength of light emitted by hydrogen atom when excited to the first excitation level is _________ nm . (Given hc = 1245eVnm, e = 1.6 × 10−19C ).

Q30.A potential divider circuit is connected with a dc source of 20 V, a light emitting diode of glow in voltage 1.8 V and a zener diode of breakdown voltage of 3.2 V. The length (PR) of the resistive wire is 20 cm. The minimum length of PQ to just glow the LED is _____ cm

Q30.A nucleus has mass number 𝐴1 and volume 𝑉1. Another nucleus has mass number 𝐴2 and volume 𝑉2. If 𝑉2 relation between mass number is 𝐴2 = 4𝐴1, then = _______. 𝑉1

Q30.The disintegration energy Q for the nuclear fission of 235U →140Ce + 94Zr + n is ______ MeV . Given atomic masses of 235U : 235.0439u; 140Ce : 139.9054u, 94Zr : 93.9063u; n : 1.0086u, Value of c2 = 931MeV/u

Q30.Radius of a certain orbit of hydrogen atom is 8.48Ã … . If energy of electron in this orbit is E/x. then x = _____ (Given a0 = 0.529Ã … , E = energy of electron in ground state).

Q30.An electron of hydrogen atom on an excited state is having energy En = −0. 85 eV. The maximum number of allowed transitions to lower energy level is _______.

Q30.The mass defect in a particular reaction is 0 . 4 g. The amount of energy liberated is 𝑛× 107 kW h, where 𝑛= _____. (speed of light = 3 × 108 m s-1)

Q30.In a nuclear fission process, a high mass nuclide (A ≈236) with binding energy 7. 6 MeV /Nucleon dissociated into two middle mass nuclides (A ≈118), having binding energy of 8. 6 MeV /Nucleon. The energy released in the process would be _______ MeV .

Q30.If three helium nuclei combine to form a carbon nucleus then the energy released in this reaction is _____ ×10−2MeV . (Given 1u = 931MeV/c2 , atomic mass of helium = 4.002603u )

Q30.Hydrogen atom is bombarded with electrons accelerated through a potential different of V , which causes excitation of hydrogen atoms. If the experiment is being formed at T = 0 K. The minimum potential difference needed to observe any Balmer series lines in the emission spectra will be α V , where α = 10 _________.(Write the value to the nearest integer)

Q30.The radius of a nucleus of mass number 64 is 4 . 8 fermi. Then the mass number of another nucleus having radius of 4 fermi is 1000 where 𝑥 is _________. 𝑥,

Q30.In an experiment to measure the focal length ( 𝑓) of a convex lens, the magnitude of object distance ( 𝑥) and the image distance ( 𝑦) are measured with reference to the focal point of the lens. The 𝑦- 𝑥 plot is shown in figure. The focal length of the lens is _____cm .

Q30.When a hydrogen atom going from n = 2 to n = 1 emits a photon, its recoil speed is x5 m s−1 . Where x = _______. (Use: mass of hydrogen atom = 1. 6 × 10−27 kg , charge of electron e = 1. 6 × 10−19 C)