Electromagnetism Test. 2

This is the correct formula for motional EMF when the field, velocity, and conductor are mutually perpendicular.

The formula for the magnetic field is B = μ₀nI, where n = N/L. If N is doubled, n is doubled, and B is doubled.

A galvanometer is the core instrument designed to detect and measure minute electric currents.

The core is built from thin, insulated iron sheets. This lamination increases the overall resistance and confines the eddy currents to small loops, significantly reducing energy loss.

A large series resistor (a multiplier) limits the current flowing through the galvanometer, allowing the device to be connected in parallel with a component to measure a large potential difference.

Due to its geometry, the magnetic field lines are completely contained within the windings of an ideal toroid.

Soft iron is easily magnetized and demagnetized, making it ideal for creating a strong temporary magnet.

These induced currents circulate within the core, and due to the core's resistance, they dissipate energy in the form of heat (I²R losses).

Back EMF is proportional to the rotational speed of the motor's armature. The faster it spins, the greater the rate of change of flux, and the larger the back EMF.

This is one of the core concepts of Maxwell's equations (specifically, the Maxwell-Ampere law). A changing electric field acts as a source of a magnetic field.

The forces on opposite sides of the coil create a turning couple, or torque, which causes the coil to rotate.

For zero deflection, qE = qvB, which simplifies to v = E/B. v = (600 N/C) / (0.02 T) = 30000 m/s = 3 x 10⁴ m/s.

The magnetic field produced by one wire interacts with the current in the other wire, resulting in a force that pulls them together.

The magnetic force formula is F = qvBsin(θ). If the velocity v=0, the force is zero. Magnetic fields only exert forces on moving charges.

Faraday's Law states that E = -N (dΦ/dt), meaning the EMF is proportional to how quickly the flux changes.

The angle θ between velocity and the magnetic field is 0 degrees. Since sin(0 degrees)=0, the magnetic force is zero, and the particle continues undeflected.

Since inductance L = Φ / I, its unit is Weber per Ampere.

According to the formula F = qvBsin(θ), the force is directly proportional to the velocity 'v'.

Using the formula E = 1/2 LI², we get E = 1/2 * (5) * (2²) = 1/2 * (5) * (4) = 10 J.

The movement of molten iron and nickel in the outer core creates a self-sustaining dynamo effect, generating the Earth's magnetic field.