Practice Questions

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.In a double slit experiment shown in figure, when light of wavelength 400 nm is used, dark fringe is observed at P . If D = 0. 2 m, the minimum distance between the slits S1 and S2 is α mm . Write the value of 10α to the nearest integer. JEE Main 2024 (29 Jan Shift 1) JEE Main Previous Year Paper

Q29.A capacitor of reactance 4√3Ω and a resistor of resistance 4Ω are connected in series with an ac source of peak value 8√2 V . The power dissipation in the circuit is ________ W.

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.If Rydberg's constant is R, the longest wavelength of radiation in Paschen series will be 7𝑅, where 𝛼= ______.

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.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.The shortest wavelength of the spectral lines in the Lyman series of hydrogen spectrum is 915Ã … . The longest wavelength of spectral lines in the Balmer series will be _____ Ã … .

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.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.A particular hydrogen - like ion emits the radiation of frequency 3 × 1015 Hz when it makes transition from 𝑥 𝑛= 2 to 𝑛= 1 . The frequency of radiation emitted in transition from 𝑛=3 to 𝑛= 1 is × 1015 Hz, when 9 𝑥= _____.

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.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.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.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

Q51.In an atom, total number of electrons having quantum numbers n = 4, | ml| = 1 and ms = −12 is ______

Q51.Consider the following reaction: 3PbCl2 + 2NH43PO4 →Pb3PO42 + 6NH4Cl If 72 mmol PbCl2 is mixed with 50 mmol of NH43PO4, then amount of Pb3PO42 formed in mmol. (nearest integer)

Q51.The de-Broglie's wavelength of an electron in the 4th orbit is πa0 ⋅(a0 = Bohr's radius ) JEE Main 2024 (04 Apr Shift 1) JEE Main Previous Year Paper

Q51.The molarity of 1L orthophosphoric acid H3PO4 having 70% purity by weight (specific gravity 1 .54 g cm−3 ) is ______ M. (Molar mass of H3PO4 = 98 g mol-1) o

Q51.Based on Heisenberg's uncertainty principle, the uncertainty in the velocity of the electron to be found within an atomic nucleus of diameter 10−15 m is ________. 109 ms−1 (nearest integer) [Given : mass of electron = 9.1 × 10−31 kg, Plank's constant (h) = 6.626 × 10−34Js] (Value of π = 3.14)

Q51.Molarity (M) of an aqueous solution containing x g of anhyd. CuSO4 in 500 mL solution at 32∘C is 2 × 10−1M. Its molality will be ______ ×10−3 m . (nearest integer). [Given density of the solution = 1.25 g/mL]

Q51.The total number of molccules with zero dipole moment among CH4, BF3, H2O, HF, NH3, CO2 and SO2 is ______.

Q51.Number of compounds with one lone pair of electrons on central atom amongst following is _ O3, H2O, SF4, ClF3, NH3, BrF5, XeF4

Q52.Lowest Oxidation number of an atom in a compound A2B is -2 . The number of an electron in its valence shell is