Practice Questions

Q11.A parallel plate capacitor with plate area A and plate separation d = 2 m has a capacitance of 4 μF. The new capacitance of the system if half of the space between them is filled with a dielectric material of dielectric constant K = 3 (as shown in figure) will be JEE Main 2022 (26 Jun Shift 2) JEE Main Previous Year Paper (1) 2 μF (2) 32 μF (3) 6 μF (4) 8 μF

Q11.A. The drift velocity of electrons decreases with the increase in the temperature of conductor. B. The drift velocity is inversely proportional to the area of cross-section of given conductor. C. The drift velocity does not depend on the applied potential difference to the conductor. D. The drift velocity of electron is inversely proportional to the length of the conductor. E. The drift velocity increases with the increase in the temperature of conductor. Choose the correct answer from the options given below: (1) A and B only (2) A and D only (3) B and E only (4) B and C only

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.Capacitance of an isolated conducting sphere of radius R1 becomes n times when it is enclosed by a concentric conducting sphere of radius R2 connected to earth. The ratio of their radii ( R2R1 ) is: (1) n (2) 2n n−1 2n+1 (3) n+1 (4) 2n+1 n n

Q11.Two sources of equal emfs are connected in series. This combination is connected to an external resistance R. The internal resistances of the two sources are r1 and r2(r1 > r2). If the potential difference across the source of internal resistance r1 is zero then the value of R will be JEE Main 2022 (27 Jul Shift 1) JEE Main Previous Year Paper (1) r1 −r2 (2) r1r2 r1+r2 (3) r1+r2 (4) r2 −r1 2

Q11.Two identical thin metal plates has charge 𝑞1 and 𝑞2 respectively such that 𝑞1 > 𝑞2. The plates were brought close to each other to form a parallel plate capacitor of capacitance 𝐶. The potential difference between them is : 𝑞1 + 𝑞2 𝑞1 - 𝑞2 (1) (2) 𝐶 𝐶 𝑞1 - 𝑞2 2𝑞1 - 𝑞2 (3) (4) 2𝐶 𝐶

Q11.A source of potential difference 𝑉 is connected to the combination of two identical capacitors as shown in the figure. When key 𝐾 is closed, the total energy stored across the combination is 𝐸1. Now key 𝐾 is opened and dielectric of dielectric constant 5 is introduced between the plates of the capacitors. The total energy stored 𝐸1 across the combination is now 𝐸2. The ratio will be 𝐸2 1 2 (1) (2) 10 5 5 5 (3) (4) 13 26

Q11.A spherically symmetric charge distribution is considered with charge density varying as ρ0( 34 −rR ) for r ≤R ρ(r) = { Zero for r > R Where, r(r < R) is the distance from the centre O (as shown in figure). The electric field at point P will be : (1) 4ε0 ρ0r ( 43 −rR ) (2) ρ0r3ε0 ( 43 −rR ) (3) ρ0r 4ε0 (1 −rR ) (4) ρ0r5ε0 (1 −rR )

Q11.A longitudinal wave is represented by y = 10 sin 2π(nt −xλ ) cm. The maximum particle velocity will be four times the wave velocity if the determined value of wavelength is equal to (1) 2π (2) 5π (3) π (4) 5π 2

Q11.The equation of a particle executing simple harmonic motion is given by x = sin π(t + 13 ) m. At t = 1 s, the speed of particle will be (Given: π = 3. 14) (1) 157 cm s−1 (2) 0 cm s−1 (3) 272 cm s−1 (4) 314 cm s−1

Q11.A vertical electric field of magnitude 4. 9 × 105 N C−1 just prevents a water droplet of a mass 0. 1 g from falling. The value of charge on the droplet will be : (Given g = 9. 8 m s−2 ) (1) 1. 6 × 10−9C (2) 2. 0 × 10−9C (3) 3. 2 × 10−9C (4) 0. 5 × 10−9C

Q11.A wire of resistance 𝑅1$R_{1}$ is drawn out so that its length is increased by twice of its original length. The ratio of new resistance to original resistance is: (1) 9: 1 (2) 1: 9 (3) 4: 1 (4) 3: 1

Q11.Two identical charged particles each having a mass 10 g and charge 2. 0 × 10−7C are placed on a horizontal table with a separation of L between them such that they stay in limited equilibrium. If the coefficient of friction between each particle and the table is 0. 25, find the value of L. [Use g = 10 ms−2 ] (1) 12 cm (2) 10 cm (3) 8 cm (4) 5 cm

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

Q11.Two point charges Q each are placed at a distance d apart. A third point charge q is placed at a distance x from mid-point on the perpendicular bisector. The value of x at which charge q will experience the maximum Coulomb's force is: (1) d (2) d 2 (3) d (4) d √2 2√2

Q11.Match List - I with List - II. List-I List-II (A) AC generator (I) Detects the presence of current in the circuit (B) Galvanometer (II) Converts mechanical energy into electrical energy (C) Transformer (III) Works on the principle of resonance in AC circuit (D) Metal detector (IV) Changes an alternating voltage for smaller or greater value (1) A - II, B - I, C - IV, D - III (2) A - II, B - I, C - III, D - IV (3) A - III, B - IV, C - II, D - I (4) A - III, B - I, C - II, D - IV

Q11.Two charged particles, having same kinetic energy, are allowed to pass through a uniform magnetic field perpendicular to the direction of motion. If the ratio of radii of their circular paths is 6: 5 and their respective masses ratio is 9: 4. Then, the ratio of their charges will be (1) 8: 5 (2) 5: 4 (3) 5: 3 (4) 8: 7 JEE Main 2022 (25 Jul Shift 1) JEE Main Previous Year Paper

Q11.The three charges 2 q , q and 2q are placed at the corners A, D and C of a square of side a as shown in figure. The magnitude of electric field (E) at the corner B of the square, is (1) + 4πϵ0a2 + 21 ) (2) 4πϵ0a2q (1 1 ) q ( √21 √2 (3) − 4πϵ0a2 q (1 √2 1 ) (4) 4πϵ0a2q ( √21 −12 )

Q12.A force of 10 N acts on a charged particle placed between two plates of a charged capacitor. If one plate of capacitor is removed, then the force acting on that particle will be. (1) 5 N (2) 10 N (3) 20 N (4) Zero

Q12.The current sensitivity of a galvanometer can be increased by : (A) decreasing the number of turns (B) increasing the magnetic field (C) decreasing the area of the coil (D) decreasing the torsional constant of the spring Choose the most appropriate answer from the options given below : (1) (B) and (C) only (2) (C) and (D) only (3) (A) and (C) only (4) (B) and (D) only

Q12.A magnet hung at 45° with magnetic meridian makes an angle of 60° with the horizontal. The actual value of the angle of dip is 2 (1) tan−1(√3 ) (2) tan−1(√6) (3) (4) 3 2 tan−1(√2 ) tan−1(√1 )

Q12.If wattless current flows in the AC circuit, then the circuit is : (1) Purely Resistive circuit (2) Purely Inductive circuit (3) LCR series circuit (4) RC series circuit only 𝑡- 𝑥

Q12.A long solenoid carrying a current produces a magnetic field 𝐵 along its axis. If the current is doubled and the number of turns per cm is halved, the new value of magnetic field will be equal to JEE Main 2022 (25 Jun Shift 2) JEE Main Previous Year Paper (1) 2𝐵 (2) 4𝐵 𝐵 (3) (4) 𝐵 2

Q12.A battery of 6 V is connected to the circuit as shown below. The current 𝐼 drawn from the battery is (1) 1 A (2) 2 A (3) 6 A (4) 4 A 11 3 JEE Main 2022 (26 Jul Shift 2) JEE Main Previous Year Paper