Electromagnetic Induction

CBSE Class 12 Physics · every board question from this chapter, 2023–2026

• A square loop of side 50 cm is placed in a uniform magnetic field of 3‧0 T acting perpendicular to the plane of the loop. If the…2026
• A closely wound long solenoid of self-inductance L is cut into two identical solenoids. The value of self-inductance of each…2026
• A square loop of side 0.50 m is placed in a uniform magnetic field of 0.4 T perpendicular to the plane of the loop. The loop is…2026
• The dimensions of the rate of change of magnetic flux are:2026
• A square loop of side L lies in the x-y plane in a magnetic field B=B_0(2 i+3 j+4 k), where B_0 is a constant. The magnetic flux…2026
• The magnetic flux through a loop placed in a magnetic field can be changed by changing:2026
• Two identical conductors 1 and 2 are placed on two frictionless conducting rails R and S in a uniform magnetic field directed…2026
• Figure shows a magnet dropped through a small loop with a small cut. Which of the following statements is correct?2026
• A metallic rod of 1 m length is rotated with a frequency of 40 rev/s, with one end hinged at the centre and the other end at the…2026
• The magnetic flux φ (in Wb ) linked with a coil is related to time t (in s) as φ=5 At^2+Bt-2 C The SI units of A and B are…2026
• Two identical circular loops A and B of metal wire are arranged on a table close to each other. Loop A is connected to a battery…2026
• A rectangular loop of size 5 cm × 8 cm is lying in x-y plane in a uniform magnetic field B=(2 · 0 T) k. The total magnetic flux…2026
• Two coils are placed closed to each other. The mutual inductance of the pair of coils depends upon the:2026
• A magnet held vertically, with its north pole down is dropped along the axis of a closed solenoid placed vertically on a table.…2026
• Assertion: Induced emf produced in a coil will be more when the magnetic flux linked with the coil is more. Reason (R): Induced…2026
• A light copper ring is freely suspended by a light string. A bar magnet is held horizontally with its length along the axis of…2026
• A plane circular coil is rotated about its vertical diameter with a constant angular speed ω in a uniform horizontal magnetic…2026
• A square loop of side 10 cm, free to rotate about a vertical axis coinciding with its one arm, is initially held perpendicular to…2026
• The figure given below shows a square-shaped loop MNOP of side 25 cm placed horizontally in a uniform magnetic field B directed…2026
• A long solenoid of length L and radius r_1 having N_1 turns is surrounded symmetrically by a coil of radius r_2(>r_1) having N_2…2026
• (i) Define mutual inductance of a pair of coils. Write its SI unit. (ii) A long solenoid of radius R and length L has n turns per…2026
• A conducting rectangular loop of area 5 cm^2 and resistance 4 Ω is removed from a region of uniform magnetic field, acting normal…2026
• State Faraday's law of electromagnetic induction. Briefly describe two methods for producing induced emf.2026
• Two coils, one of radius 0.5 cm having 10 turns and the other of radius 5 cm having 50 turns are placed coaxially in air such…2026
• State Faraday's law of electromagnetic induction. Derive an expression for the self-inductance of an air-filled long solenoid of…2026
• A rectangular coil of area A is kept in a uniform magnetic field B such that the plane of the coil makes an angle α with B. The…2025
• A vertically held bar magnet is dropped along the axis of a copper ring having a cut as shown in the diagram. The acceleration of…2025
• A circular coil of diameter 15 mm having 300 turns is placed in a magnetic field of 30 mT such that the plane of the coil is…2025
• A coil has 100 turns, each of area 0.05 m^2 and total resistance 1.5 Ω. It is inserted at an instant in a magnetic field of 90…2025
• A soft iron rod X is allowed to fall on the two poles of a U shaped permanent magnet as shown in figure. A coil is wrapped over…2025
• In the figure X is a coil wound over a hollow wooden pipe. A permanent magnet is pushed at a constant speed v from the right into…2025
• You are required to design an air-filled solenoid of inductance 0.016 H having a length 0.81 m and radius 0.02 m. The number of…2025
• Two long solenoids of radii r_1 and r_2(>r_1) and number of turns per unit length n_1 and n_2 respectively are co-axially wrapped…2025
• The magnetic flux linked with a closed coil (in Wb ) varies with time t (in s ) as φ=5 t^2+4 t-2. If the resistance of the…2025
• The magnetic flux linked with a coil changes with time t as φ=(8 t^2+5 t+7), where t is in seconds and φ is in Wb. The value of…2025
• When current in a coil changes at a steady rate from 8 A to 6 A in 4 ms, an emf of 1.5 V is induced in it. The value of…2025
• A metal rod of length 50 cm is held vertically and moved with a velocity of 10 m / s towards east. The horizontal component of…2025
• The dimensions of 'self-inductance' are:2025
• A coil of an ac generator, having 100 turns and area 0.1 m^2 each, rotates at half a rotation per second in a magnetic field of…2025
• Assertion: It is difficult to move a magnet into a coil of large number of turns when the circuit of the coil is closed. Reason…2025
• State Lenz's law. In the given figure: (i) Identify the machine. (ii) Name the parts P and Q and R of the machine. (iii) Give the…2025
• Two coils ' 1 ' and ' 2 ' are placed close to each other as shown in the figure. Find the direction of induced current in coil '…2025
• Differentiate between magnetic flux through an area and magnetic field at a point. A bar magnet is held with its length along the…2025
• Consider two long co-axial solenoids S_1 and S_2, each of length l(≫ r_2) and of radius r_1 and r_2(r_2>r_1). The number of turns…2025
• Show that the energy required to build up the current I in a coil of inductance L is 1/2 L^2. Considering the case of magnetic…2025
• State Faraday's law of electromagnetic induction and explain the role of negative sign in its expression. Explain, with an…2025
• State Lenz's law. A rod MN of length L is rotated about an axis passing through its end M perpendicular to its length, with a…2025
• Obtain an expression for the self-inductance of a long solenoid of length ' l ', cross-sectional area 'A' and having ' N ' turns.…2025
• A parallel plate capacitor is charged by an ac source. Show that the sum of conduction current (I_c) and the displacement current…2025
• Two concentric circular coils of radii r_1 and r_2(r_2 ≫ r) are placed coaxially with their centres coinciding. If a current I is…2025
• (i) Define self-inductance of a coil. Derive the expression for the energy required to build up a current I in a coil of…2025
• (i) State Lenz's law and explain how this law is a consequence of conservation of energy principle. (ii) A square shaped loop of…2025
• The emf induced in a coil rotating in a magnetic field does not depend upon the following:2024
• A conducting loop is placed in a magnetic field, normal to its plane. The magnitude of the magnetic field varies with time as…2024
• A circular coil of radius 10 cm is placed in a magnetic field B=(1.0 i+0.5 j) mT such that the outward unit vector normal to the…2024
• Which of the following quantity/quantities remains same in primary and secondary coils of an ideal transformer? Current, Voltage,…2024
• The mutual inductance of two coils, in a given orientation is 50 mH. If the current in one of the coils changes as i=1.0 sin (100…2024
• Two coils are placed near each other. When the current in one coil is changed at the rate of 5 A / s, an emf of 2 mV is induced…2024
• A coil of area of cross-section 0.5 m^2 is placed in a magnetic field acting normally to its plane. The field varies as B=0.5…2024
• The current in a coil of 15 mH increases uniformly from zero to 4 A in 0.004 s. The emf induced in the coil will be:2024
• A coil of N turns is placed in a magnetic field B such that B is perpendicular to the plane of the coil. B changes with time as…2024
• The mutual inductance of two coils C_1 and C_2 is 20 mH. In coil C_1, the current changes from 4 A to zero in 0 · 2 s. If the…2024
• Consider a solenoid of length l and area of cross-section A with fixed number of turns. The self-inductance of the solenoid will…2024
• A conducting circular loop is placed in a uniform magnetic field B=50 mT with its plane perpendicular to the magnetic field. The…2024
• Assertion: The mutual inductance between two coils is maximum when the coils are wound on each other. Reason (R): The flux…2024
• Assertion: Lenz's law is a consequence of the law of conservation of energy. Reason (R): There is no power loss in an ideal…2024
• A 100 -turn coil of radius 1.6 cm and resistance 5.0 Ω is co-axial with a solenoid of 250 turns / cm and radius 1.8 cm. The…2024
• Prove that induced charge depends on the net change in the magnetic flux and not on the time interval of the flux change.2024
• A rectangular loop of sides 10 cm × 20 cm is kept outside a region of uniform magnetic field | B|=5 mT as shown in the figure.…2024
• (i) State Lenz's Law. In a closed circuit, the induced current opposes the change in magnetic flux that produced it as per the…2024
• Consider the arrangement of two coils P and Q shown in the figure. When current in coil P is switched on or switched off, a…2024
• (i) Define mutual inductance. Write its SI unit. (ii) Derive an expression for the mutual inductance of a system of two long…2024
• (i) (1) What is meant by current sensitivity of a galvanometer? Mention the factors on which it depends. (2) A galvanometer of…2024
• Two identical circular coaxial coils A and B, arranged in vertical planes parallel to each other, carry currents in the same…2023
• A square shaped coil of side 10 cm, having 100 turns is placed perpendicular to a magnetic field which is increasing at 1 T / s.…2023
• A capacitor is charged by a battery. Between the plates, during process of charging:2023
• A circular coil of radius 8.0 cm and 40 turns is rotated about its vertical diameter with an angular speed of 25/(π) rad s^-1 in…2023
• Figure shows a rectangular conductor PSRQ in which movable arm PQ has a resistance ' r ' and resistance of PSRQ is negligible.…2023
• In the process of charging of a capacitor, the current produced between the plates of the capacitor is:2023
• The direction of induced current in the loop abc is:2023
• A bar magnet is dropped in a hollow metallic cylinder along its vertical axis. The acceleration of the falling magnet will be:2023
• Consider an induced magnetic field due to changing electric field and an induced electric field due to changing magnetic field.…2023
• Two coils C_1 and C_2 are placed close to each other. The magnetic flux φ_2 linked with the coil C_2 varies with the current I_1…2023
• What is meant by the term 'mutual inductance' of a pair of coils? Obtain an expression for the mutual inductance of two long…2023
• The figure shows the variation of induced emf as a function of rate of change of current for two identical solenoids X and Y. One…2023
• A long solenoid of radius r consists of n turns per unit length. A current I=I_0 sin ω t flows in the solenoid. A coil of N turns…2023
• The figure shows a rectangular conductor PQRS in which the arm PQ of length 10 cm and resistance 0 · 4 Ω is free to move. It is…2023
• State the basic principle behind the working of an ac generator. Briefly describe its working and obtain the expression for the…2023
• A rectangular loop of sides 25 cm and 20 cm is lying in x-y plane. It is subjected to a magnetic field B=(5 t^2+2 t+10) k, where…2023
• Two coplanar concentric circular loops of radii R and r(≪ R) are arranged coaxially. Obtain the expression for their mutual…2023
• A rectangular conductor MNPQ with a movable arm MN (resistance r ) is kept in a uniform magnetic field as shown in the figure.…2023
• (i) Define coefficient of self-induction. Obtain an expression for self-inductance of a long solenoid of length l, area of cross-…2023
• Consider the experimental set up shown in the figure. This jumping ring experiment is an outstanding demonstration of some simple…2023

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