Practice Questions

Q25.The electric potential at the surface of an atomic nucleus ( 𝑍= 50 ) of radius 9 × 10-13 cm is 𝛼× 106 V. What is the value of 𝛼? (Charge of proton 1 . 6 × 10-19 C)

Q25.In the given circuit, the current flowing through the resistance 20 Ω is 0. 3 A, while the ammeter reads 0. 9 A. The value of R1 is _____ Ω .

Q25.A parallel plate capacitor with plate separation 5 mm is charged up by a battery. It is found that on introducing a dielectric sheet of thickness 2 mm, while keeping the battery connections intact, the capacitor draws 25% more charge from the battery than before. The dielectric constant of the sheet is ____.

Q25.Two identical charged spheres are suspended by strings of equal lengths. The strings make an angle 𝜃 with each other. When suspended in water the angle remains the same. If density of the material of the sphere is 1 . 5 g / cc, the dielectric constant of water will be ______. (Take density of water = 1 g / cc)

Q25.A capacitor of 10μF capacitance whose plates are separated by 10 mm through air and each plate has area 4 cm2 is now filled equally with two dielectric media of K1 = 2, K2 = 3 respectively as shown in figure. If new force between the plates is 8 N . The supply voltage is _________ ×10−4 V . (we modified language of question to make it correct)

Q25.An electric field, E = √6 passes through the surface of 4 m2 area having unit vector ^n = ( √6 ) electric flux for that surface is ______ Vm .

Q25.An infinite plane sheet of charge having uniform surface charge density +σsC/m2 is placed on x −y plane. Another infinitely long line charge having uniform linear charge density +λeC/m is placed at z = 4 m plane and parallel to y-axis. If the magnitude values |σs| = 2 |λe| then at point (0, 0, 2), the ratio of magnitudes of electric field values due to sheet charge to that of line charge is π√n : 1. The value of n is_______.

Q25.At the centre of a half ring of radius R = 10 cm and linear charge density 4nCm−1 , the potential is xπV . The value of x is _______ JEE Main 2024 (09 Apr Shift 1) JEE Main Previous Year Paper

Q25.The electric field between the two parallel plates of a capacitor of 1.5μF capacitance drops to one third of its initial value in 6.6μs when the plates are connected by a thin wire. The resistance of this wire is _____ Ω . (Given, log 3 = 1.1 )

Q25.Suppose a uniformly charged wall provides a uniform electric field of 2 × 104 N C-1 normally. A charged particle of mass 2 g being suspended through a silk thread of length 20 cm and remain stayed at a distance 1 of 10 cm from the wall. Then the charge on the particle will be 𝜇C where 𝑥= ________ [use √x 𝑔= 10 m s-2]

Q25.The distance between charges +𝑞 and -𝑞 is 2𝑙 and between +2𝑞 and -2𝑞 is 4𝑙. The electrostatic potential at point 𝑃 at a distance 𝑟 from centre 𝑂 is -𝛼𝑞𝑙 × 109 V, where the value of 𝛼 is ______. (Use 𝑟2 1 = 9 × 109 N m2 C-2) 4𝜋𝜀0 2

Q25.A point source is emitting sound waves of intensity 16 × 10-8 W m-2 at the origin. The difference in intensity (magnitude only) at two points located at a distances of 2 m and 4 m from the origin respectively will be ________ × 10-8 W m-2.

Q25.If the net electric field at point P along Y axis is zero, then the ratio of q2 is 8 , where x = _____. q3 5√x

Q25.The electric field at point p due to an electric dipole is E. The electric field at point R on equitorial line will be E . The value of x : x

Q26.The charge accumulated on the capacitor connected in the following circuit is ______ μC. (Given C = 150 μF)

Q26.Equivalent resistance of the following network is ________ 𝛺.

Q26.Two charges of -4 μC and +4 μC are placed at the points 𝐴( 1, 0, 4 ) m and 𝐵( 2, - 1, 5 ) m located in an electric field →𝐸= 0 . 20 ^i V cm-1. The magnitude of the torque acting on the dipole is 8√𝛼× 10-5 N m, where 𝛼= _________.

Q26.Two identical charged spheres are suspended by strings of equal lengths. The string make an angle of 37° with each other. When suspended in a liquid of density 0 . 7 g cm-3, the angle remains same. If density of material 3 of the sphere is 1 . 4 g cm-3, the dielectric constant of the liquid is _____ tan37° = 4

Q26.A wire of resistance R and radius r is stretched till its radius became r/2. If new resistance of the stretched wire is xR, then value of x is _______ →

Q26.The current in a conductor is expressed as 𝐼= 3𝑡2 + 4𝑡3, where 𝐼 is in Ampere and 𝑡 is in second. The amount of electric charge that flows through a section of the conductor during 𝑡= 1 s to 𝑡= 2 s is ____________ C .

Q26.An electric field →E = (2x^i)NC −1 exists in space. A cube of side 2 m is placed in the space as per figure given below. The electric flux through the cube is ______ Nm2/C. JEE Main 2024 (09 Apr Shift 2) JEE Main Previous Year Paper

Q26.A charge of 4. 0 μC is moving with a velocity of 4. 0 × 106 m s−1 along the positive y-axis under a magnetic field B of strength T. The force acting on the charge is xˆi N. The value of x is ______. (2ˆk)

Q26.Two wires A and B are made up of the same material and have the same mass. Wire A has radius of 2.0 mm and wire B has radius of 4.0 mm. The resistance of wire B is 2Ω. The resistance of wire A is _____ Ω. JEE Main 2024 (04 Apr Shift 2) JEE Main Previous Year Paper

Q26.Two cells are connected in opposition as shown. Cell E1 is of 8 V emf and 2 Ω internal resistance; the cell E2 is of 2 V emf and 4 Ω internal resistance. The terminal potential difference of cell E2 is ______ V .

Q26.A heater is designed to operate with a power of 1000 W in a 100 V line. It is connected in combination with a resistance of 10Ω and a resistance R, to a 100 V mains as shown in figure. For the heater to operate at 62.5 W, the value of R should be _____ Ω.