Practice Questions

Q18.The mass number of nucleus having radius equal to half of the radius of nucleus with mass number 192 is: (1) 24 (2) 32 (3) 40 (4) 20

Q18.The radius of third stationary orbit of electron for Bohr's atom is R. The radius of fourth stationary orbit will be: (1) 4 R (2) 16 R 3 9 (3) 3 R (4) 9 R 4 16

Q18.The work function of a substance is 3. 0 eV. The longest wavelength of light that can cause the emission of photoelectrons from this substance is approximately: (1) 215 nm (2) 414 nm (3) 400 nm (4) 200 nm

Q18.The atomic mass of 6C12 is 12 . 000000 u and that of 6C13 is 13 . 003354 u. The required energy to remove a neutron from 6C13 , if mass of neutron is 1 . 008665 u, will be: (1) 62 . 5MeV (2) 6 . 25MeV (3) 4 . 95MeV (4) 49 . 5MeV

Q18.The angular momentum of an electron in a hydrogen atom is proportional to : (Where r is the radius of orbit of electron) (1) r (2) √r (3) 1 (4) 1 √r r

Q18.The longest wavelength associated with Paschen series is : (Given RH = 1.097 × 107SI unit) (1) 3.646 × 10−6 m (2) 1.876 × 10−6 m (3) 2.973 × 10−6 m (4) 1.094 × 10−6 m

Q18.The energy equivalent of 1 g of substance is : (1) 5.6 × 1012MeV (2) 5.6 × 1026MeV (3) 11.2 × 1024MeV (4) 5.6eV

Q18.Monochromatic light of frequency 6 × 1014 Hz is produced by a laser. The power emitted is 2 × 10-3 W . How many photons per second on an average, are emitted by the source? (Given h = 6 . 63 × 10-34 J s) (1) 9 × 1018 (2) 6 × 1015 (3) 5 × 1015 (4) 7 × 1016

Q18.The de-Broglie wavelength of an electron is the same as that of a photon. If velocity of electron is 25% of the velocity of light, then the ratio of K.E. of electron and K.E. of photon will be: (1) 1 (2) 1 1 8 (3) 8 (4) 1 1 4

Q18.Which figure shows the correct variation of applied potential difference (V) with photoelectric current (I) at two different intensities of light (I1 < I2) of same wavelengths : (1) (2) (3) (4)

Q18.Binding energy of a certain nucleus is 18 × 108 J. How much is the difference between total mass of all the nucleons and nuclear mass of the given nucleus: (1) 10μg (2) 20μg (3) 0.2μg (4) 2μg

Q18.The energy released in the fusion of 2 kg of hydrogen deep in the sun is EH and the energy released in the fission of 2 kg of 235U is EU . The ratio EHEU is approximately: (Consider the fusion reaction as 4 ∣H + 2e−→42He + 2v + 6γ + 26.7MeV, energy released in the fission reaction of 235U is 200MeV per fission nucleus and NA = 6.023 × 1023) JEE Main 2024 (09 Apr Shift 2) JEE Main Previous Year Paper (1) 7.62 (2) 25.6 (3) 15.04 (4) 9.13

Q18.According to Bohr's theory, the moment of momentum of an electron revolving in 4th orbit of hydrogen atom is: (1) h (2) h π 2π (3) 8 hπ (4) 2 hπ JEE Main 2024 (04 Apr Shift 2) JEE Main Previous Year Paper

Q18.Two sources of light emit with a power of 200 W. The ratio of number of photons of visible light emitted by each source having wavelengths 300 nm and 500 nm respectively, will be : (1) 1 : 5 (2) 1 : 3 (3) 5 : 3 (4) 3 : 5

Q18.In a hypothetical fission reaction 92X 236 →56Y 141 + 36Z 92 + 3R The identity of emitted particles ( R) is : (1) Electron (2) Neutron (3) γ -radiations (4) Proton 1

Q18.The minimum energy required by a hydrogen atom in ground state to emit radiation in Balmer series is nearly : (1) 1 . 5 eV (2) 13 . 6 eV (3) 1 . 9 eV (4) 12 . 1 eV

Q19.An electron rotates in a circle around a nucleus having positive charge Ze. Correct relation between total energy (E) of electron to its potential energy (U) is : (1) E = U (2) 2E = U (3) 2E = 3U (4) E = 2U

Q19.If the wavelength of the first member of Lyman series of hydrogen is 𝜆. The wavelength of the second member will be 27 32 (1) 32𝜆 (2) 27𝜆 (3) 27 𝜆 (4) 5 5 27𝜆

Q19.The correct truth table for the following logic circuit is : (1) A B Y (2) A B Y 0 0 1 0 0 0 0 1 1 0 1 1 1 0 0 1 0 0 1 1 1 1 1 1 (3) A B Y (4) A B Y 0 0 1 0 0 0 0 1 1 0 1 0 1 0 0 1 0 0 1 1 0 1 1 1

Q19.The output of the given circuit diagram is JEE Main 2024 (31 Jan Shift 2) JEE Main Previous Year Paper (1) (2) (3) (4)

Q19.In the given circuit if the power rating of Zener diode is 10 mW, the value of series resistance 𝑅𝑠 to regulate the input unregulated supply is: 3 (1) 𝑘𝛺 (2) 10 𝛺 7 (3) 1 𝑘𝛺 (4) 10 𝑘𝛺 Q20.10 divisions on the main scale of a Vernier calliper coincide with 11 divisions on the Vernier scale. If each division on the main scale is of 5 units, the least count of the instrument is : (1) 1 (2) 10 2 11 (3) 50 (4) 5 11 11

Q19.The I −V characteristics of an electronic device shown in the figure. The device is: (1) a diode which can be used as a rectifier (2) a zener diode which can be used as a voltage regulator (3) a transistor which can be used as an amplifier (4) a solar cell

Q19.The ratio of the magnitude of the kinetic energy to the potential energy of an electron in the 5th excited state of a hydrogen atom is : (1) 4 (2) 14 (3) 1 (4) 1 2

Q19.The truth table of the given circuit diagram is : JEE Main 2024 (27 Jan Shift 2) JEE Main Previous Year Paper (1) A B Y (2) A B Y 0 0 1 0 0 0 0 1 0 0 1 1 1 0 0 1 0 1 1 1 1 1 1 0 (3) A B Y (4) A B Y 0 0 0 0 0 1 0 1 0 0 1 1 1 0 0 1 0 1 1 1 1 1 1 0

Q19.In the given circuit, the voltage across load resistance ( 𝑅𝐿) is: (1) 8 . 75 V (2) 9 . 00 V (3) 8 . 50 V (4) 14 . 00 V