Practice Questions

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

Q18.When a metal surface is illuminated by light of wavelength 𝜆, the stopping potential is 8 V. When the same surface is illuminated by light of wavelength 3𝜆, stopping potential is 2 V. The threshold wavelength for this surface is : (1) 5𝜆 (2) 3𝜆 (3) 9𝜆 (4) 4 . 5𝜆

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

Q19.The explosive in a Hydrogen bomb is a mixture of 1H2, 1H3 and 3Li6 in some condensed form. The chain reaction is given by 3Li6 + 0n1 →2He4 + 1H3; 1H2 + 1H3 →2He4 + 0n1 During the explosion the energy released is approximately [Given : M(Li) = 6. 01690 amu, M(1H2) = 2. 01471 amu, M(2He4) = 4. 00388 amu and 1 amu = 931. 5 MeV] (1) 28. 12 MeV (2) 12. 64 MeV (3) 16. 48 MeV (4) 22. 22 MeV

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. Identify the logic gate given in the circuit: (1) NAND-gate (2) AND gate (3) NOR gate (4) OR- gate

Q19.From the statements given below : (A) The angular momentum of an electron in 𝑛𝑡ℎ orbit is an integral multiple of ℎ. (B) Nuclear forces do not obey inverse square law. JEE Main 2024 (01 Feb Shift 2) JEE Main Previous Year Paper (C) Nuclear forces are spin dependent. (D) Nuclear forces are central and charge independent. (E) Stability of nucleus is inversely proportional to the value of packing fraction. Choose the correct answer from the options given below : (1) (A), (B), (C), (D) only (2) (A), (C), (D), (E) only (3) (A), (B), (C), (E) only (4) (B), (C), (D), (E) only

Q19.The output (Y ) of logic circuit given below is 0 only when : (1) A = 1, B = 0 (2) A = 0, B = 1 (3) A = 0, B = 0 (4) A = 1, B = 1

Q19.Which of the following nuclear fragments corresponding to nuclear fission between neutron (10n) and uranium isotope (23592 U) is correct : (1) 144 56 Ba + 8936Kr + 410n (2) 14456 Ba + 8936Kr + 310n (3) 140 56 Xe + 9438Sr + 310n (4) 15351 Sb + 9941Nb + 310n

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

Q19.A light emitting diode (LED) is fabricated using GaAs semiconducting material whose band gap is 1.42eV. The wavelength of light emitted from the LED is : (1) 1400 nm (2) 650 nm (3) 875 nm (4) 1243 nm

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.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 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.Least count of a vernier caliper is 20 N cm . The value of one division on the main scale is 1 mm . Then the number of divisions of main scale that coincide with N divisions of vernier scale is : (1) (2 N −1) (2) ( 2 2N−1N ) (3) ( 2 N−12 ) (4) ( 220N−1N )

Q19.The acceptor level of a p-type semiconductor is 6eV. The maximum wavelength of light which can create a hole would be : Given hc = 1242eVnm. (1) 414 nm (2) 103.5 nm (3) 207 nm (4) 407 nm

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.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.Which of the following circuits is reverse - biased ? (1) (2) (3) (4)

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

Q19.The output Y of following circuit for given inputs is : (1) Λ ⋅B(Λ + B) (2) 0 – (3) A ⋅B (4) A ⋅B

Q20.Conductivity of a photodiode starts changing only if the wavelength of incident light is less than 660 nm . X The band gap of photodiode is found to be eV . The value of X is: 8 (Given h = 6 . 6 × 10-34 J s, e = 1 . 6 × 10-19 C) (1) 15 (2) 11 (3) 13 (4) 21

Q20.Which of the diode circuit shows correct biasing used for the measurement of dynamic resistance of p-n junction diode : (1) (2) (3) (4)

Q20.A Zener diode of breakdown voltage 10 V is used as a voltage regulator as shown in the figure. The current through the Zener diode is (1) 50 mA (2) 0 (3) 30 mA (4) 20 mA