Practice Questions

Q10.Force between two point charges 𝑞1 and 𝑞2 placed in vacuum at 𝑟 cm apart is 𝐹. Force between them when placed in a medium having dielectric 𝐾= 5 at 𝑟 cm apart will be: 5 𝐹 (1) (2) 5𝐹 25 (3) 𝐹 (4) 25𝐹 5

Q10.The electrostatic potential due to an electric dipole at a distance r varies as : (1) r (2) 1 r2 (3) 1 (4) 1 r3 r

Q10. N moles of a polyatomic gas (f = 6) must be mixed with two moles of a monoatomic gas so that the mixture behaves as a diatomic gas. The value of N is: (1) 6 (2) 3 (3) 4 (4) 2 N C−1 . The electric flux through a surface area 30ˆi m2 lying in

Q10.Two charges of 5Q and −2Q are situated at the points (3a, 0) and (−5a, 0) respectively. The electric flux through a sphere of radius 4a having centre at origin is: (1) 2Q (2) 5Q ε0 ε0 (3) 7Q (4) 3Q ε0 ε0

Q10.Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason(R) Assertion (A) : Work done by electric field on moving a positive charge on an equipotential surface is always zero. Reason (R) : Electric lines of forces are always perpendicular to equipotential surfaces. In the light of the above statements, choose the most appropriate answer from the options given below : (1) Both (A) and (R) are correct but (R) is not the (2) (A) is correct but (R) is not correct correct explanation of (A) (3) (A) is not correct but (R) is correct (4) Both (A) and (R) are correct and (R) is the correct explanation of (A)

Q10.A particle of charge -𝑞 and mass 𝑚 moves in a circle of radius 𝑟 around an infinitely long line charge of linear density +𝜆. Then time period will be given as: (Consider 𝑘 as Coulomb's constant) (1) 𝑇2 = 4𝜋2 2𝑘𝜆𝑞𝑟3𝑚 (2) 𝑇= 2𝜋𝑟√ 2𝑘𝜆𝑞𝑚 (3) 𝑇= 1 𝑚 (4) 𝑇= 1 2𝑘𝜆𝑞 2𝜋𝑟√ 2𝑘𝜆𝑞 2𝜋√ 𝑚

Q11.Match List I with List II Chose the correct answer from the options given below (1) A −IV, B −I, C −III, D −II (2) A −II, B −III, C −I, D −IV (3) A −IV, B −III, C −I, D −II (4) A −I, B −II, C −III, D −IV

Q11.Two identical capacitors have same capacitance 𝐶. One of them is charged to the potential 𝑉 and other to the potential 2𝑉. The negative ends of both are connected together. When the positive ends are also joined together, the decrease in energy of the combined system is : 1 (1) 4𝐶𝑉2 (2) 2𝐶𝑉2 (3) 12𝐶𝑉2 (4) 34𝐶𝑉2

Q11.A proton and a deutron ( q = +e, m = 2.0u) having same kinetic energies enter a region of uniform magnetic field →B, moving perpendicular to →B. The ratio of the radius rd of deutron path to the radius rp of the proton path is: (1) √2 : 1 (2) 1 : 1 (3) 1 : √2 (4) 1 : 2

Q11.A capacitor is made of a flat plate of area A and a second plate having a stair-like structure as shown in figure. If the area of each stair is A and the height is d, the capacitance of the arrangement is : 3 (1) 13ϵoA (2) 11ϵoA 17d 18 d (3) 18ϵoA (4) 11ϵoA 11 d 20 d

Q11.A charge q is placed at the center of one of the surface of a cube. The flux linked with the cube is: (1) q (2) q 2ϵ0 8ϵ0 (3) Zero (4) q 4ϵ0

Q11.Ques: σ is the uniform surface charge density of a thin spherical shell of radius R. The electric field at any point on the surface of the spherical shell is : (1) σ/ϵoR (2) σ/ϵo (3) σ/4ϵo (4) σ/2ϵo

Q11. A galvanometer of resistance 100Ω when connected in series with 400Ω measures a voltage of upto 10 V. The value of resistance required to convert the galvanometer into ammeter to read upto 10 A is x × 10−2Ω. The value of x is : (1) 2 (2) 800 (3) 20 (4) 200

Q11.A galvanometer 𝐺 of 2𝛺 resistance is connected in the given circuit. The ratio of charge stored in 𝐶1 and 𝐶2 is: 2 3 (1) (2) 3 2 1 (3) 1 (4) 2

Q11. The parameter that remains the same for molecules of all gases at a given temperature is : (1) kinetic energy (2) momentum (3) mass (4) speed

Q11.A wire of resistance R and length L is cut into 5 equal parts. If these parts are joined parallely, then resultant resistance will be : (1) R (2) R 25 5 (3) 25R (4) 5R

Q11. The heat absorbed by a system in going through the given cyclic process is : JEE Main 2024 (05 Apr Shift 1) JEE Main Previous Year Paper (1) 19.6 J (2) 61.6 J (3) 616 J (4) 431.2 J

Q11.The number of electrons flowing per second in the filament of a 110 W bulb operating at 220 V is : ( Given e = 1.6 × 10−19C) (1) 6.25 × 1017 (2) 1.25 × 1019 (3) 6.25 × 1018 (4) 31.25 × 1017 JEE Main 2024 (06 Apr Shift 2) JEE Main Previous Year Paper

Q11.By what percentage will the illumination of the lamp decrease if the current drops by 20%? (1) 46% (2) 26% (3) 36% (4) 56%

Q11.When a potential difference 𝑉 is applied across a wire of resistance 𝑅, it dissipates energy at a rate 𝑊. If the wire is cut into two halves and these halves are connected mutually parallel across the same supply, the energy dissipation rate will become: 1 1 (1) W (2) W 4 2 (3) 2 W (4) 4 W JEE Main 2024 (30 Jan Shift 2) JEE Main Previous Year Paper

Q11.A capacitor has air as dielectric medium and two conducting plates of area 12 cm2 and they are 0.6 cm apart. When a slab of dielectric having area 12 cm2 and 0.6 cm thickness is inserted between the plates, one of the conducting plates has to be moved by 0.2 cm to keep the capacitance same as in previous case. The dielectric constant of the slab is : (Given ϵ0 = 8.834 × 10−12 F/m ) (1) 1 (2) 1.33 (3) 0.66 (4) 1.50

Q11.An electric field is given by (6ˆi + 5ˆj + 3ˆk) YZ-plane(in SI unit) is: (1) 90 (2) 150 (3) 180 (4) 60

Q11.Two charged conducting spheres of radii a and b are connected to each other by a conducting wire. The ratio of charges of the two spheres respectively is: (1) a b v (2) √ab (3) b (4) ab a

Q11.A potential divider circuit is shown in figure. The output voltage V0 is (1) 4 V (2) 2 mV (3) 0. 5 V (4) 12 mV JEE Main 2024 (30 Jan Shift 1) JEE Main Previous Year Paper

Q11.Wheatstone bridge principle is used to measure the specific resistance 𝑆1 of given wire, having length 𝐿, radius 𝜋𝑟2 𝑟. If X is the resistance of wire, then specific resistance is : 𝑆1 = 𝑋 𝐿. If the length of the wire gets doubled then the value of specific resistance will be : 𝑆1 (1) (2) 2 S1 4 (3) 𝑆1 (4) 𝑆1 2