Practice Questions

Q17.A biconvex lens of refractive index 1. 5 has a focal length of 20 cm in air. Its focal length when immersed in a liquid of refractive index 1. 6 will be: (1) −16 cm (2) −160 cm (3) +160 cm (4) +16 cm

Q17.The de Broglie wavelengths of a proton and an 𝛼 particle are 𝜆 and 2𝜆 respectively. The ratio of the velocities of proton and 𝛼 particle will be : (1) 1 : 8 (2) 1 : 2 (3) 4 : 1 (4) 8 : 1

Q17.A convex lens of focal length 40 cm forms an image of an extended source of light on a photoelectric cell. A current I is produced. The lens is replaced by another convex lens having the same diameter but focal length 20 cm. The photoelectric current now is (1) I (2) 4I 2 (3) 2I (4) I

Q17.When UV light of wavelength 300 nm is incident on the metal surface having work function 2.13eV, electron emission takes place. The stopping potential is: (Given hc = 1240eVnm ) (1) 1.5 V (2) 4.1 V (3) 2 V (4) 4 V

Q17.Which of the following statement is not true about stopping potential (V0) ? (1) It is 1/ e times the maximum kinetic energy of (2) It increases with increase in intensity of the electrons emitted. incident light. (3) It depends on the nature of emitter material. (4) It depends upon frequency of the incident light.

Q17.In a photoelectric effect experiment a light of frequency 1 . 5 times the threshold frequency is made to fall on the surface of photosensitive material. Now if the frequency is halved and intensity is doubled, the number of photo electrons emitted will be: (1) Doubled (2) Quadrupled (3) Zero (4) Halved

Q17.The diffraction pattern of a light of wavelength 400 nm diffracting from a slit of width 0. 2 mm is focused on the focal plane of a convex lens of focal length 100 cm. The width of the 1st secondary maxima will be : (1) 2 mm (2) 2 cm (3) 0. 02 mm (4) 0. 2 mm

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.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.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.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 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 ratio of the shortest wavelength of Balmer series to the shortest wavelength of Lyman series for hydrogen atom is : (1) 4 : 1 (2) 1 : 4 (3) 2 : 1 (4) 1 : 2 JEE Main 2024 (06 Apr Shift 1) JEE Main Previous Year Paper

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 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

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

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

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.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 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 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 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