Practice Questions

Q6. If p is the density and η is coefficient of viscosity of fluid which flows with a speed v in the pipe of diameter d, the correct formula for Reynolds number Re is (1) Re = πdρv (2) Re = ηdρv (3) Re = ρvdη (4) Re = ρνdη

Q6. The distance between Sun and Earth is R. The duration of year if the distance between Sun and Earth becomes 3R will be : (1) √3 yr (2) 3√3 yr (3) 3 yr (4) 9 yr

Q6. The variation of acceleration due to gravity (g) with distance (r) from the center of the earth is correctly represented by (Given R = radius of earth) (1) (2) (3) (4)

Q7. A flask contains argon and oxygen in the ratio of 3 : 2 in mass and the mixture is kept at 27°C . The ratio of their average kinetic energy per molecule respectively (1) 3 : 5 (2) 9 : 4 (3) 2 : 3 (4) 1 : 1

Q7. An object is taken to a height above the surface of earth at a distance 5 R from the centre of the earth. Where 4 radius of earth, R = 6400 km. The percentage decrease in the weight of the object will be JEE Main 2022 (25 Jul Shift 2) JEE Main Previous Year Paper (1) 36% (2) 50% (3) 64% (4) 25%

Q7. The efficiency of a Carnot's engine, working between steam point and ice point, will be (1) 26. 81% (2) 37. 81% (3) 47. 81% (4) 57. 81%

Q7. If the length of a wire is made double and radius is halved of its respective values. Then, the Young's modulus of the material of the wire will : (1) Remain same (2) Become 8 times its initial value (3) Become 1th of its initial value (4) Become 4 times its initial value 4

Q7. The ratio of specific heats in terms of degree of freedom 𝑓 is given by : 𝐶𝑉 (1) 1 + 𝑓 (2) 1 + 2 3 𝑓 (3) 1 + 𝑓 (4) 1 + 1 2 𝑓

Q8. A monoatomic gas at pressure P and volume V is suddenly compressed to one eighth of its original volume. The final pressure at constant entropy will be (1) P (2) 8P (3) 32P (4) 64P

Q8. In the figure, a very large plane sheet of positive charge is shown. 𝑃1 and 𝑃2 are two points at distance 𝑙 and 2𝑙 from the charge distribution. If 𝜎 is the surface charge density, then the magnitude of electric fields 𝐸1 and 𝐸2 at 𝑃1 and 𝑃2 respectively are JEE Main 2022 (25 Jun Shift 1) JEE Main Previous Year Paper 𝜎 𝜎 2𝜎 𝜎 (1) 𝐸1 = 𝜀𝑜, 𝐸2 = 2𝜀𝑜 (2) 𝐸1 = 𝜀𝑜, 𝐸2 = 𝜀𝑜 𝜎 𝜎 (3) 𝐸1 = 𝐸2 = (4) 𝐸1 = 𝐸2 = 2𝜀𝑜 𝜀𝑜

Q8. A radar sends an electromagnetic signal of electric field (E0) = 2. 25 V m−1 and magnetic field (B0) = 1. 5 × 10−8 T which strikes a target on line of sight at a distance of 3 km in a medium. After that, a part of signal (echo) reflects back towards the radar with same velocity and by same path. If the signal was transmitted at time t = 0 from radar, then after how much time echo will reach to the radar? (1) 2. 0 × 10−5 s (2) 4. 0 × 10−5 s (3) 1. 0 × 10−5s (4) 8. 0 × 10−5s

Q8. Two metallic blocks M1 and M2 of same area of cross-section are connected to each other (as shown in figure). If the thermal conductivity of M2 is K then the thermal conductivity of M1 will be : [Assume steady state heat conduction] JEE Main 2022 (24 Jun Shift 1) JEE Main Previous Year Paper (1) 10K (2) 8K (3) 12. 5K (4) 2K

Q9. When a particle executes simple Harmonic motion, the nature of graph of velocity as function of displacement will be (1) Circular (2) Ellipitical (3) Sinusoidal (4) Straight line

Q9. In the wave equation 𝑦= 0 . 5sin 𝜆400𝑡- 𝑥𝑚 the velocity of the wave will be : (1) 200 m s-1 (2) 200√2 m s-1 (3) 400 m s-1 (4) 400√2 m s-1

Q9. For a perfect gas, two pressures P1 and P2 are shown in figure. The graph shows (1) P1 > P2 (2) P1 < P2 (3) P1 = P2 (4) Insufficient data to draw any conclusion

Q10.A long straight wire with a circular cross-section having radius 𝑅, is carrying a steady current 𝐼. The current 𝐼 is uniformly distributed across this cross-section. Then the variation of magnetic field due to current 𝐼 with distance 𝑟𝑟< 𝑅 from its centre will be (1) 𝐵∝𝑟 (2) 𝐵∝1 𝑟 1 (3) 𝐵∝𝑟2 (4) 𝐵∝ 𝑟2

Q10.A condenser of 2 𝜇F capacitance is charged steadily from 0 to 5 C. Which of the following graph represents correctly the variation of potential difference𝑉 across its plates with respect to the charge 𝑄 on the condenser? (1) (2) (3) (4)

Q10.The displacement of simple harmonic oscillator after 3 seconds starting from its mean position is equal to half of its amplitude. The time period of harmonic motion is (1) 12 s (2) 8 s (3) 36 s (4) 6 s

Q10.A charge of 4μC is to be divided into two. The distance between the two divided charges is constant. The magnitude of the divided charges so that the force between them is maximum, will be: (1) 1μC and 3μC (2) 2μC and 2μC (3) 0 and 4μC (4) 1. 5μC and 2. 5μC

Q11.The current I in the given circuit will be (1) 10A (2) 20A (3) 4A (4) 40A + T. If it has an acceleration of

Q11.An observer moves towards a stationary source of sound with a velocity one-fifth of the velocity of sound. The percentage change in the apparent frequency is (1) zero (2) 5% (3) 10% (4) 20%

Q11.Two point charges A and B of magnitude +8 × 10−6C and −8 × 10−6C respectively are placed at a distance d apart. The electric field at the middle point O between the charges is 6. 4 × 104 N C−1 . The distance ' d' between the point charges A and B is (1) 2 m (2) 3 m (3) 1 m (4) 4 m

Q12.If the electric potential at any point (x, y, z) m in space is given by V = 3x2 volt. The electric field at the point (1, 0, 3) m will be : (1) 3 Vm−1 , directed along positive x-axis. (2) 3 Vm−1 , directed along negative x-axis. (3) 6 Vm−1 , directed along negative x-axis. (4) 6 Vm−1 , directed along positive x-axis.

Q12.Given below are two statements. Statement I : Electric potential is constant within and at the surface of each conductor. Statement II : Electric field just outside a charged conductor is perpendicular to the surface of the conductor at every point. JEE Main 2022 (29 Jul Shift 1) JEE Main Previous Year Paper In the light of the above statements, choose the most appropriate answer from the options give below. (1) Both statement I and statement II are correct (2) Both statement I and statement II are incorrect (3) Statement I is correct but statement II is incorrect (4) Statement I is incorrect but and statement II is correct

Q12.If a wave gets refracted into a denser medium, then which of the following is true? (1) Wavelength, speed and frequency decreases. (2) Wavelength increases, speed decreases and frequency remains constant. (3) Wavelength and speed decreases but frequency (4) Wavelength, speed and frequency increases. remains constant.