Electromagnetic Induction

Problem 169: A magnetic coil produces 100,000 maxwells with 2,000 turns and with a current of 2 A. The current is cut-off and the flux collapses in 0.01 sec. What is the average voltage that will appear across the coil?

Problem 170: A magnet, which generates 800 maxwells of flux, is inserted through a coil of 1000 turns. It is then withdrawn within 0.15 sec. What is the voltage that appears across the coil?

Problem 171: The armature coil of a generator with 50 conductors on it rotates in a magnetic field with a magnetic flux density 1.5 T. The effective area of the coil is 1000 square cm. If this coil is move across the pole in 0.5 sec, determine the average emf induced in the coil.

Problem 172: A conductor, 50 mm long, moves at a velocity of 2.5 meters per second across a magnetic field of \(0.90\,Wb/m^2\). What is the voltage generated?

Problem 174: A piece of conductor 10 cm long moves across a magnetic field of 10,000 gauss at a velocity of 120 cm/sec. What voltage appears across the conductor?

Problem 175: A conductor 50 cm in length moves at an angle of 30° to the direction of a magnetic field with a velocity of 100 cm/s. If the field has a flux density of \(2\,Wb/m^2\), calculate the emf induced in it.

Problem 178: How much is the inductance of a coil that induces 500 V when the current changes at the rate of 5 mA in 2 \(\mu s\)?

Problem 181: An iron core 0.4 m long and 5 square cm. in cross section, is wound with 300 turns. When a current of 0.5 A flows in the coil, how much is the inductance of the coil. Assume the core has a permeability of 2500.

Problem 182: What is the coefficient of coupling of two coils whose mutual inductance is 1 H and whose self-inductance are 1.2 and 2 H?

Problem 188: The energy (Wo) stored in a coil is dependent in the inductance (L) of the coil and the current flowing. If the inductance were doubled with the same current flowing, what would be the resulting stored energy?

Problem 189: A 6.0 H coil whose resistance is 12 ohms is connected in series with a 24 ohms resistor and to a 144 V battery and a switch. The switch is closed at t = 0. Determine the energy stored in the magnetic field at steady state.

Coil 1 of a pair of coupled coils has a continuous current of 5 A, and the corresponding fluxes \(\Phi_{11}\) and \(\Phi_{12}\) are 0.2 and 0.4 mWb, respectively. Find the coupling coefficient k.

A coil of inductance 8 mH produces 80 μWb of magnetic flux. Of this total flux, 60 μWb are linked to a second coil of inductance 2 mH. How much is the mutual inductance between the coils?

Two inductors of 20 mH and 10 mH are connected in series carrying a current of 1 A. Find the stored energy.

A coil of inductance 8 mH produces 80 μWb of magnetic flux. Of this total flux, 60 μWb are linked to a second coil of inductance 2 mH. How much is the mutual inductance between the coils?

An inductance of 8 mH is in series with the parallel combination of 3 mH and 6 mH. What is the equivalent inductance ?

When one coil of a magnetically coupled pair has a current of 5 A, the resulting fluxes \(\phi_{11}\) and \(\phi_{12}\) are 0.4 and 0.8 mWb, respectively. If the turns are \(N_1\) = 500 and \(N_2\) = 1,500, find M.

Calculate the self-inductance of an air-cored solenoid, 40cm long having an area of cross-section 20cm² and 800 turns.

A piece of conductor 10 cm long moves across a magnetic field of 10,000 gauss at a velocity of 120 cm/sec. What voltage appears across the conductor?

On triling the number of turns of a coil the inductance