Practice Questions

Q16.In normal adjustment, for a refracting telescope, the distance between objective and eye piece is 30 cm. The focal length of the objective, when the angular magnification of the telescope is 2, will be: (1) 20 cm (2) 30 cm (3) 10 cm (4) 15 cm 1 . 227

Q17.Which is the correct ascending order of wavelengths? (1) λvisible < λX−ray < λgamma−ray < λmicrowave (2) λgamma−ray < λX−ray < λvisible < λmicrowave (3) λX−ray < λgamma−ray < λvisible < λmicrowave (4) λmicrowave < λvisible < λgamma−ray < λX−ray

Q17.Two streams of photons, possessing energies to five and ten times the work function of metal are incident on the metal surface successively. The ratio of the maximum velocities of the photoelectron emitted, in the two cases respectively, will be (1) 1 : 2 (2) 1 : 3 (3) 2 : 3 (4) 3 : 2

Q17.In the following circuit, the correct relation between output (Y ) and inputs A and B will be JEE Main 2022 (28 Jun Shift 1) JEE Main Previous Year Paper (1) Y = A ⋅B (2) Y = A + B (3) Y = A ⋅B (4) Y = A + B

Q17.A parallel beam of light of wavelength 900 nm and intensity 100 Wm−2 is incident on a surface perpendicular to the beam. The number of photons crossing 1 cm2 area perpendicular to the beam in one second is (1) 3 × 1016 (2) 4. 5 × 1016 (3) 4. 5 × 1017 (4) 4. 5 × 1020

Q18.An unpolarised light beam of intensity 2𝐼0 is passed through a polaroid 𝑃 and then through another polaroid 𝑄 which is oriented in such a way that its passing axis makes an angle of 30° relative to that of 𝑃. The intensity of the emergent light is (1) 𝐼0 (2) 𝐼0 4 2 3𝐼0 3𝐼0 (3) (4) 4 2 JEE Main 2022 (29 Jul Shift 2) JEE Main Previous Year Paper

Q18.What is the half-life period of a radioactive material if its activity drops to 1 of its initial value of 30 years ? 16th (1) 9. 5 years (2) 8. 5 years (3) 7. 5 years (4) 10. 5 years JEE Main 2022 (27 Jul Shift 1) JEE Main Previous Year Paper

Q18.Mass numbers of two nuclei are in the ratio of 4: 3. Their nuclear densities will be in the ratio of (1) 4: 3 (2) 3 13 4 (3) 1: 1 (4) 4 13 3

Q18.The half life period of a radioactive substance is 60 days. The time taken for 7 th of its original mass to 8 disintegrate will be : (1) 120 days (2) 130 days (3) 180 days (4) 20 days

Q18.The ratio for the speed of the electron in the 3rd orbit of He+ to the speed of the electron in the 3rd orbit of hydrogen atom will be : (1) 1: 1 (2) 1: 2 (3) 4: 1 (4) 2: 1

Q18.A radioactive sample decays 7 times its original quantity in 15 minutes. The half-life of the sample is 8 (1) 5 min (2) 7. 5 min (3) 15 min (4) 30 min

Q18.Find the modulation index of an AM wave having 8 V variation where maximum amplitude of the AM wave is 9 V . (1) 0. 8 (2) 0. 5 (3) 0. 2 (4) 0. 1 JEE Main 2022 (29 Jul Shift 1) JEE Main Previous Year Paper

Q19.The maximum and minimum voltage of an amplitude modulated signal are 60 V and 20 V respectively. The percentage modulation index will be (1) 0 . 5% (2) 50% (3) 2% (4) 30% JEE Main 2022 (26 Jul Shift 2) JEE Main Previous Year Paper

Q19.Nucleus A is having mass number 220 and its binding energy per nucleon is 5. 6 MeV . It splits in two fragments B and C of mass numbers 105 and 115 . The binding energy of nucleons in B and C is 6. 4 MeV per nucleon. The energy Q released per fission will be: (1) 0. 8 MeV (2) 275 MeV (3) 220 MeV (4) 176 MeV

Q20.Identify the correct Logic Gate for the following output (Y ) of two inputs A and B . (1) (2) (3) (4)

Q20.The TV transmission tower at a particular station has a height of 125 m . For doubling the coverage of its range, the height of the tower should be increased by (1) 500 m (2) 375 m (3) 250 m (4) 125 m

Q20.Match List-I with List-II List-I List-II (A) Television signal I. 03 KHz (B) Radio signal II. 20 KHz (C) High Quality Music III. 02 MHz (D) Human speech IV. 06 MHz (1) A −I, B −II, C −III, D −IV (2) A −IV, B −III, C −I, D −II (3) A −IV, B −III, C −II, D −I (4) A −I, B −II, C −IV, D −III

Q20.A FM Broad cast transmitter, using modulating signal of frequency 20 kHz has a deviation ratio of 10 . The Bandwidth required for transmission is : (1) 220 kHz (2) 180 kHz (3) 360 kHz (4) 440 kHz

Q20.At a particular station, the TV transmission tower has a height of 100 m. To triple its coverage range, height of the tower should be increased to (1) 200 m (2) 300 m (3) 600 m (4) 900 m

Q20.A screw gauge of pitch 0. 5 mm is used to measure the diameter of uniform wire of length 6. 8 cm, the main scale reading is 1. 5 mm and circular scale reading is 7 . The calculated curved surface area of wire to appropriate significant figures is [Screw gauge has 50 divisions on the circular scale] (1) 6. 8 cm2 (2) 3. 4 cm2 (3) 3. 9 cm2 (4) 2. 4 cm2

Q20.A signal of 100THz frequency can be transmitted with maximum efficiency by (1) Coaxial cable (2) Optical fibre (3) Twisted pair of copper wires (4) Water

Q20.In AM modulation, a signal is modulated on a carrier wave such that maximum and minimum amplitude are found to be 6 V and 2 V respectively. The modulation index is (1) 100% (2) 80% (3) 60% (4) 50%

Q20.Amplitude modulated wave is represented by VAM = 10[1 + 0. 4 cos(2π × 104t)] cos(2π × 107t). The total bandwidth of the amplitude modulated wave is (1) 10 kHz (2) 20 MHz (3) 20 kHz (4) 10 MHz

Q31.Consider the reaction 4HNO3l + 3KCls →Cl2g + NOClg + 2H2Og + 3KNO3s The amount of HNO3 required to produce110 . 0 g of KNO3 is (Given : Atomic masses of H, O, N and K are 1, 16, 14 and 39, respectively.) (1) 32 . 2 g (2) 69 . 4 g (3) 91 . 5 g (4) 162 . 5 g

Q31.Using the rules for significant figures, the correct answer for the expression 0.02858×0.112 will be: 0.5702 (1) 0. 005613 (2) 0. 00561 (3) 0. 0056 (4) 0. 006