Electromagnetic Induction Test. 6

The total charge that flows (Q = ∫I dt) is measured and is proportional to the initial magnetic flux (Φ), and thus the magnetic field B.

By definition, a step-up transformer has more turns in the secondary coil than the primary, resulting in a higher output voltage.

Magnetic moment is pole strength times length. If you break a magnet of length L in half, each new magnet has length L/2, and the new magnetic moment will be half of the original.

An induced electric field forms closed loops. The work done in moving a charge around a closed loop in this field is not zero. Therefore, it is a non-conservative field.

Faraday's discovery of electromagnetic induction is the fundamental principle behind every commercial electric generator.

The power factor is cos(φ). For a pure inductor or capacitor, the phase angle φ = 90 degrees. Since cos(90 degrees) = 0, the average power consumed is zero.

The formula is L = (μ₀N²A)/l. The new inductance L' = (μ₀(2N)²A)/(2l) = 2 * (μ₀N²A)/l = 2L.

As the brushes on the commutator make and break contact, sparking can occur. A small capacitor placed across the motor terminals can suppress this high-frequency noise.

The constant change in current of AC creates a continuous back EMF (inductive reactance) that opposes the flow. A steady DC current has no change, so it only faces the inductor's small ohmic resistance.

High permeability strengthens the magnetic field. Low retentivity means it loses its magnetism quickly when the current is turned off, which is desired for an electromagnet.

By the Right-Hand Rule, the wire creates a magnetic field directed **into the page** through the loop. Since the wire's current is increasing, this 'into the page' flux increases. To oppose this change, Lenz's Law dictates that the induced current must create a magnetic field **out of the page**. A counter-clockwise current is required to produce this opposing field.

The formula for instantaneous EMF is ε = ε₀ sin(θ). ε = ε₀ sin(30 degrees) = ε₀ / 2.

When pushed in, the flux increases, inducing a current in one direction. When pulled out, the flux decreases, inducing a current in the opposite direction, according to Lenz's law.

Using the formula ε = B * L * v * sin(θ): ε = (0.8 T)(0.5 m)(10 m/s) * sin(30 degrees) = (4)(0.5) = 2 V.

Mutual inductance (M) is a physical property of the transformer, determined by its construction. It does not depend on the frequency of the AC supply.

This is the very definition of self-inductance. It creates a back EMF that opposes any increase or decrease in the current, acting as a form of electrical inertia.