Practice Questions

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.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.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

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.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.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 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.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.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

Q12.A square loop of side 15 cm being moved towards right at a constant speed of 2 cm/s as shown in figure. The front edge enters the 50 cm wide magnetic field at t = 0 . The value of induced emf in the loop at t = 10 s will JEE Main 2024 (09 Apr Shift 2) JEE Main Previous Year Paper be : (1) 0.3mV (2) zero (3) 4.5mV (4) 3mV

Q12.If the collision frequency of hydrogen molecules in a closed chamber at 27∘C is Z, then the collision frequency of the same system at 127∘C is : (1) √3 2 z (2) √32 Z (3) 3 4 Z (4) 34 Z

Q12.An electric bulb rated 50 W −200 V is connected across a 100 V supply. The power dissipation of the bulb is: (1) 25 W (2) 12.5 W (3) 50 W (4) 100 W

Q12.The resistance per centimeter of a meter bridge wire is 𝑟, with 𝑋 𝛺 resistance in left gap. Balancing length from left end is at 40 cm with 25 𝛺 resistance in right gap. Now the wire is replaced by another wire of 2𝑟 resistance per centimeter. The new balancing length for same settings will be at (1) 20 cm (2) 10 cm (3) 80 cm (4) 40 cm

Q12.In a metre-bridge when a resistance in the left gap is 2 Ω and unknown resistance in the right gap, the balance length is found to be 40 cm . On shunting the unknown resistance with 2 Ω, the balance length changes by: (1) 22 . 5 cm (2) 20 cm (3) 62 . 5 cm (4) 65 cm JEE Main 2024 (01 Feb Shift 2) JEE Main Previous Year Paper

Q12.The reading in the ideal voltmeter 𝑉 shown in the given circuit diagram is: (1) 5 V (2) 10 V (3) 0 V (4) 3 V

Q12.An electric toaster has resistance of 60 Ω at room temperature (27 °C). The toaster is connected to a 220 V supply. If the current flowing through it reaches 2. 75 A, the temperature attained by toaster is around: (if α = 2 × 10−4 ∘C−1 ) (1) 694°C (2) 1235°C (3) 1694°C (4) 1667°C

Q12.The ratio of heat dissipated per second through the resistance 5Ω and 10Ω in the circuit given below is : (1) 1 : 2 (2) 2 : 1 (3) 4 : 1 (4) 1 : 1 −

Q12.A galvanmeter has a coil of resistance 200Ω with a full scale deflection at 20μA. The value of resistance to be added to use it as an ammeter of range (0 −20)mA is ; (1) 0.40Ω (2) 0.20Ω (3) 0.50Ω (4) 0.10Ω

Q12.The fundamental frequency of a closed organ pipe is equal to the first overtone frequency of an open organ pipe. If length of the open pipe is 60 cm, the length of the closed pipe will be : (1) 60 cm (2) 45 cm (3) 30 cm (4) 15 cm

Q12.An alternating voltage 𝑉( 𝑡) = 220sin100𝜋t volt is applied to a purely resistive load of 50 𝛺. The time taken for the current to rise from half of the peak value to the peak value is: (1) 5 ms (2) 3 . 3 ms (3) 7 . 2 ms (4) 2 . 2 ms

Q12. Match List-I with List-II : Choose the correct answer from the options given below : (1) (A)-(IV), (B)-(I), (C)-(III), (D)-(II) (2) (A)-(I), (B)-(III), (C)-(II), (D)-(IV) (3) (A)-(III), (B)-(IV), (C)- (I), (D)-(II) (4) (A)-(III), (B)-(I), (C)-(IV), (D)-(II)

Q12.In the given circuit, the current in resistance R3 is: (1) 1 A (2) 1. 5 A (3) 2 A (4) 2. 5 A

Q12.A wire of length 10 cm and radius √7 × 10−4 m connected across the right gap of a meter bridge. When a resistance of 4. 5 Ω is connected on the left gap by using a resistance box, the balance length is found to be at 60 cm from the left end. If the resistivity of the wire is R × 10−7 Ω m , then value of R is : (1) 63 (2) 70 (3) 66 (4) 35

Q12.The value of unknown resistance (x) for which the potential difference between B and D will be zero in the arrangement shown, is : (1) 3Ω (2) 42Ω (3) 9Ω (4) 6Ω

Q12.A capacitor of capacitance 100 μF is charged to a potential of 12 V and connected to a 6. 4 mH inductor to produce oscillations. The maximum current in the circuit would be : (1) 3. 2 A (2) 1. 5 A (3) 2. 0 A (4) 1. 2 A