Practice Questions

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

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.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.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.A hydrogen atom changes its state from n = 3 to n = 2. Due to recoil, the percentage change in the wave length of emitted light is approximately 1 × 10−n . The value of n is_____. [Given Rhc = 13.6eV, hc = 1242eVnm, h = 6.6 × 10−34 J s mass of the hydrogenatom = 1.6 × 10−27 kg ] JEE Main 2024 (04 Apr Shift 1) JEE Main Previous Year Paper

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.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.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.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.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= _____.

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.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 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

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.Volume of 3M NaOH (formula weight 40 g mol-1 ) which can be prepared from 84 g of NaOH is ____ × 10-1dm3. Q52.9 . 3 g of aniline is subjected to reaction with excess of acetic anhydride to prepare acetanilide. The mass of acetanilide produced if the reaction is 100% completed is _____ × 10-1 g. (Given molar mass in g mol-1 N = 14, O = 16, C = 12, H = 1 ) Q53.1 mole of PbS is oxidised by X moles of O3 to get Y moles of O2 . X + Y =

Q51.Consider the following reactions NiS + HNO3 + HCl →A + NO + S + H2O A + NH4OH + H3C −C = N −OH | →B + NH4Cl + H2O The number of protons that do not involve in H3C −C = N −OH hydrogen bonding in the product B is ______.

Q51.Number of moles of methane required to produce 22g CO2 ( g ) after combustion is x × 10 – 2 moles. The value of x is

Q51.Wavenumber for a radiation having 5800Ã … wavelength is x × 10 cm−1 . The value of x is ________ (Integer answer)

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 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