Practice Questions

Q26.An α particle, a proton and an electron have the same kinetic energy. Which one of the following is correct in case of their de-Broglie wavelength: (1) λα > λp > λe (2) λα < λp < λe (3) λα = λp = λe (4) λα > λp < λe

Q26.The threshold frequency of metal is f0 . When the light of frequency 2f0 is incident on the metal plate, the maximum velocity of photoelectron is v1 . When the frequency of incident radiation is increased to 5f0 . the maximum velocity of photoelectrons emitted is v2 . The ratio of v1 to v2 is: (1) v1 v2 = 21 (2) v2v1 = 81 (3) v1 v2 = 161 (4) v2v1 = 41

Q26.The ratio of de-Broglie wavelength of an α -particle and a proton accelerated from rest by the same potential is 1 , the value of m is: √m JEE Main 2023 (29 Jan Shift 2) JEE Main Previous Year Paper (1) 4 (2) 16 (3) 8 (4) 2

Q27.A 12. 5 eV electron beam is used to bombard gaseous hydrogen at room temperature. The number of spectral lines emitted will be: (1) 1 (2) 4 (3) 2 (4) 3

Q27.An electron of a hydrogen like atom, having Z = 4 , jumps from 4th energy state to 2nd energy state, The energy released in this process, will be: (Given Rch = 13. 6 eV ) Where R = Rydberg constant c = Speed of light in vacuum h = Planck's constant (1) 13. 6 eV (2) 10. 5 eV (3) 3. 4 eV (4) 40. 8 eV

Q27.Substance A has atomic mass number 16 and half life of 1 day. Another substance B has atomic mass number 32 and half life of 21 day. If both A and B simultaneously start undergo radio activity at the same time with initial mass 320 g each, how many total atoms of A and B combined would be left after 2 days (1) 3. 38 × 1024 (2) 6. 76 × 1024 (3) 6. 76 × 1023 (4) 1. 69 × 1024

Q27.For a nucleus AZX having mass number A and atomic number Z = –a1A 3 . A. The surface energy per nucleon (bs) 2 B. The Coulomb contribution to the binding energy bc = −a2 Z(Z−1)4 . A 3 JEE Main 2023 (08 Apr Shift 1) JEE Main Previous Year Paper C. The volume energy bv = a3A D. Decrease in the binding energy is proportional to surface area. E. While estimating the surface energy, it is assumed that each nucleon interacts with 12 nucleons. ( a1, a2 and a3 are constants) Choose the most appropriate answer from the options given below: (1) B, C, E only (2) C, D only (3) A, B, C, D only (4) B, C only

Q27.A photon is emitted in transition from n = 4 to n = 1 level in hydrogen atom. The corresponding wavelength for this transition is (given, h = 4 × 10−15 eV s ) (1) 941 nm (2) 974 nm (3) 99. 3 nm (4) 94. 1 nm

Q27.The radius of electron's second stationary orbit in Bohr's atom is R. The radius of 3rd orbit will be (1) R (2) 2. 25 R 3 (3) 3R (4) 9R

Q27.The ratio of the de-Broglie wavelengths of proton and electron having same kinetic energy: (Assume mp = me × 1849 ) (1) 1 : 43 (2) 1 : 30 (3) 1 : 62 (4) 2 : 43

Q28.The ratio of the density of oxygen nucleus (168O) and helium nucleus (42He) is (1) 4 : 1 (2) 8 : 1 (3) 1 : 1 (4) 2 : 1

Q28.A radio active material is reduced to 1 of its original amount in 3 days. If 8 × 10−3 kg of the material is left 8 after 5 days the initial amount of the material is (1) 40 g (2) 32 g (3) 64 g (4) 256 g

Q28.For the following circuit and given inputs A and B, choose the correct option for output ‵Y ′ JEE Main 2023 (13 Apr Shift 1) JEE Main Previous Year Paper (1) (2) (3) (4)

Q28.The work functions of Aluminium and Gold are 4. 1 eV and 5. 1 eV respectively. The ratio of the slope of the stopping potential versus frequency plot for Gold to that of Aluminium is (1) 1. 24 (2) 2 (3) 1 (4) 1. 5

Q28.For the given logic gates combination, the correct truth table will be (1) A B X (2) A B X 0 0 1 0 0 0 0 1 0 0 1 1 1 0 0 1 0 1 1 1 0 1 1 0 (3) A B X (4) A B X 0 0 1 0 0 0 0 1 0 0 1 1 1 0 1 1 0 1 1 1 0 1 1 1

Q28.The energy of He+ ion in its first state is, (The ground state energy for the Hydrogen atom −13. 6 eV): (1) −27. 2 eV (2) −3. 4 eV (3) −13. 6 eV (4) −54. 4 eV

Q28.Which of the following statement is not correct in the case of light emitting diodes? A. It is a heavily doped p-n junction. B. It emits light only when it is forward biased. C. It emits light only when it is reverse biased. D. The energy of the light emitted is equal to or slightly less than the energy gap of the semiconductor used. Choose the correct answer from the options given below : (1) C and D (2) A (3) C (4) B

Q29.The energy levels of an atom is shown is figure. Which one of these transitions will result in the emission of a photon of wavelength 124. 1 nm? Given ( h = 6. 62 × 10–34 J s) JEE Main 2023 (25 Jan Shift 2) JEE Main Previous Year Paper (1) B (2) A (3) C (4) D

Q29.For a given transistor amplifier circuit in CE configuration VCC = 1 V, RC = 1 kΩ, Rb = 100 kΩ and β = 100 . Value of base current Ib is JEE Main 2023 (08 Apr Shift 2) JEE Main Previous Year Paper (1) Ib = 1. 0 μA (2) Ib = 0. 1 μA (3) Ib = 100 μA (4) Ib = 10 μA

Q29.The logic gate equivalent to the given circuit diagram is : JEE Main 2023 (24 Jan Shift 2) JEE Main Previous Year Paper (1) OR (2) NAND (3) NOR (4) AND

Q29.If the height of transmitting and receiving antennas are 80 m each, the maximum line of sight distance will be : Given : Earth’s radius = 6. 4 × 106 m . (1) 32 km (2) 28 km (3) 36 km (4) 64 km

Q29.In an n-p-n common emitter (CE) transistor the collector current changes from 5 mA to 16 mA for the change in base current from 100 μA and 200 μA, respectively. The current gain of transistor is _____. (1) 110 (2) 210 (3) 0. 9 (4) 9

Q29.The output Y for the inputs A and B of circuit is given by Truth table of the shown circuit is : (1) A B Y (2) A B Y ⎡ 0 0 1 ⎤ ⎡ 0 0 1 ⎤ 0 1 1 0 1 0 1 0 1 1 0 0 1 1 0 1 1 1 ⎣ ⎦ ⎣ ⎦ (3) A B Y (4) A B Y ⎡ 0 0 0 ⎤ ⎡ 0 0 0 ⎤ 0 1 1 0 1 1 1 0 1 1 0 1 1 1 1 1 1 0 ⎣ ⎦ ⎣ ⎦

Q29.Choose the correct statement about Zener diode: (1) It works as a voltage regulator in reverse bias and (2) It works as a voltage regulator in both forward behaves like simple p-n junction diode in forward and reverse bias bias (3) It works a voltage regulator only in forward bias (4) It works as a voltage regulator in forward bias and behaves like simple p-n junction diode in reverse bias

Q29.The logic operations performed by the given digital circuit is equivalent to: (1) NOR (2) AND (3) OR (4) NAND