Practice Questions

Q16.Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R. Assertion A : If an electric dipole of dipole moment 30 × 10–5 C m is enclosed by a closed surface, the net flux coming out of the surface will be zero. Reason R : Electric dipole consists of two equal and opposite charges. In the light of above, statements, choose the correct answer from the options given below. JEE Main 2023 (12 Apr Shift 1) JEE Main Previous Year Paper (1) Both A and R are true and R is the correct (2) A is false but R is true explanation of A (3) A is true but R is false (4) Both A and R are true and R is NOT the correct explanation of A

Q16.As shown in figure, a cuboid lies in a region with electric field E = 2x2ˆi −4yˆj + 6ˆk N C−1 . The magnitude of charge within the cuboid is nε0 C. The value of n is ______ (if dimension of cuboid is 1 × 2 × 3 m3 )

Q16.Two parallel plate capacitors C1 and C2 each having capacitance of 10 μF are individually charged by a 100 V D.C. source. Capacitor C1 is kept connected to the source and a dielectric slab is inserted between it plates. Capacitor C2 is disconnected from the source and then a dielectric slab is inserted in it. Afterwards the capacitor C1 is also disconnected from the source and the two capacitors are finally connected in parallel combination. The common potential of the combination will be _____ V . (Assuming Dielectric constant = 10 )

Q17.As shown in the figure, two parallel plate capacitors having equal plate area of 200 cm2 are joined in such a way that a ≠b. The equivalent capacitance of the combination is xε0F . The value of x is _____.

Q17.In the given circuit. C1 = 2μF, C2 = 0. 2μF, C3 = 2μF, C4 = 4μF, C5 = 2μF, C6 = 2μF. The charge stored on capacitor C4 is ______ μC. JEE Main 2023 (11 Apr Shift 2) JEE Main Previous Year Paper

Q17.A cell of emf 90 V is connected across series combination of two resistors each of 100 Ω resistance. A voltmeter of resistance 400 Ω is used to measure the potential difference across each resistor. The reading of the voltmeter will be: (1) 40 V (2) 45 V (3) 80 V (4) 90 V

Q17.An electric dipole of dipole moment is 6. 0 × 10−6 C m placed in a uniform electric field of 1. 5 × 103 N C−1 in such a way that dipole moment is along electric field. The work done in rotating dipole by 180° in this field will be_______ mJ.

Q18.In the given circuit, the equivalent resistance between the terminal A and B is ____ Ω

Q18.A potential V0 is applied across a uniform wire of resistance R. The power dissipation is P1. The wire is then cut into two equal halves and a potential of V0 is applied across the length of each half. The total power dissipation across two wires is P2. The ratio of P2 : P1 is √x : 1. The value of x is _____.

Q18.The number density of free electrons in copper is nearly 8 × 1028 m−3 . A copper wire has its area of cross- section = 2 × 10−6 m2 and is carrying a current of 3. 2 A . The drift speed of the electrons is _____ ×10−6 m s−1 .

Q18.A null point is found at 200 cm in potentiometer when cell in secondary circuit is shunted by 5 Ω . When a resistance of 15 Ω is used for shunting null point moves to 300 cm . The internal resistance of the cell is ______ Ω .

Q18.A capacitor has capacitance 5 µF when its parallel plates are separated by air medium of thickness d. A slab of material of dielectric constant 1. 5 having area equal to that of plates but thickness d2 is inserted between the plates. Capacitance of the capacitor in the presence of slab will be ______ µF .

Q18.If the potential difference between B and D is zero, the value of x is n1 Ω. The value of n is ______.

Q19.In the given circuit the value of I1+I3 is: I2

Q19.Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R. Assertion A: Photodiodes are preferably operated in reverse bias condition for light intensity measurement. Reason R: The current in the forward bias is more than the current in the reverse bias for a 𝑝- 𝑛 junction diode. In the light of the above statement, choose the correct answer from the options given below : JEE Main 2023 (24 Jan Shift 1) JEE Main Previous Year Paper (1) A is false but R is true (2) Both A and R are true but R is NOT the correct explanation of A (3) A is true but R is false (4) Both A and R are true and R is the correct explanation of A

Q19.When a resistance of 5 Ω is shunted with a moving coil galvanometer, it shows a full scale deflection for a current of 250 mA, however when 1050 Ω resistance is connected with it in series, it gives full scale deflection for 25 volt. The resistance of galvanometer is _________Ω.

Q19.A long solenoid is formed by winding 70 turns cm−1 . If 2. 0 A current flows, then the magnetic field produced inside the solenoid is ______________. (µ0 = 4π × 10–7 T m A–1) (1) 1232 × 10–4 T (2) 176 × 10–4 T (3) 352 × 10–4 T (4) 88 × 10–4 T

Q19.Two identical cells each of emf 1. 5 V are connected in series across a 10 Ω resistance. An ideal voltmeter connected across 10 Ω resistance reads 1. 5 V . The internal resistance of each cell is _____ Ω.

Q19.A current of 2 A flows through a wire of cross-sectional area 25. 0 mm2 . The number of free electrons in a cubic meter are 2. 0 × 1028 . The drift velocity of the electrons is _____ ×10−6 ms−1 (given, charge on electron = 1. 6 × 10−19C).

Q19.Given below are two statements: Statement I : The diamagnetic property depends on temperature. Statement II : The induced magnetic dipole moment in a diamagnetic sample is always opposite to the magnetising field. In the light of given statements, choose the correct answer from the options given below (1) Both Statement I and Statement II are False (2) Statement I is incorrect but Statement II is true (3) Statement I is correct but Statement II is false (4) Both Statement I and Statement II are true

Q19.For the given circuit, in the steady state, |VB −VD| = _____ V .

Q20.The ratio of magnetic field at the centre of a current carrying coil of radius r to the magnetic field at distance r from the centre of coil on its axis is √x : 1 . The value of x is _____.

Q20.In an experiment with vernier callipers of least count 0 . 1 mm, when two jaws are joined together the zero of vernier scale lies right to the zero of the main scale and 6th division of vernier scale coincides with the main scale division. While measuring the diameter of a spherical bob, the zero of vernier scale lies in between 3 . 2 cm and 3 . 3 cm marks and 4th division of vernier scale coincides with the main scale division. The diameter of bob is measured as (1) 3 . 22 cm (2) 3 . 18 cm (3) 3 . 26 cm (4) 3 . 25 cm JEE Main 2023 (10 Apr Shift 2) JEE Main Previous Year Paper

Q20.Two cells are connected between points A and B as shown. Cell 1 has emf of 12 V and internal resistance of 3 Ω. Cell 2 has emf of 6 V and internal resistance of 6 Ω. An external resistor R of 4 Ω is connected across A and B. The current flowing through R will be ______ A .

Q20.As shown in the figure the voltmeter reads 2 V across 5 Ω resistor. The resistance of the voltmeter is _____ Ω