E & M - flux

Front

What is electromagnetic flux?

Back

Electromagnetic flux is the measure of the quantity of magnetism, taking into account the strength and extent of a magnetic field. It is defined as the product of the magnetic field (B) and the area (A) through which the field lines pass, and is given by the formula: Φ = B * A * cos(θ), where θ is the angle between the magnetic field lines and the normal (perpendicular) to the surface.

Front

What is the formula for calculating induced emf in a loop of wire?

Back

The induced electromotive force (emf) in a loop of wire can be calculated using Faraday's law of electromagnetic induction, which states: emf = -dΦ/dt, where dΦ is the change in magnetic flux and dt is the change in time.

Front

What is the significance of the negative sign in Faraday's law?

Back

The negative sign in Faraday's law indicates the direction of the induced emf and current, as described by Lenz's law. It states that the induced emf will always work to oppose the change in magnetic flux that produced it.

Front

How does the area of a loop affect the magnetic flux?

Back

The magnetic flux through a loop is directly proportional to the area of the loop. A larger area allows more magnetic field lines to pass through, resulting in greater flux.

Front

What is the relationship between the angle of the magnetic field and the area vector in calculating flux?

Back

The angle between the magnetic field and the area vector affects the calculation of magnetic flux. The flux is maximized when the angle is 0 degrees (field lines are perpendicular to the surface) and is zero when the angle is 90 degrees (field lines are parallel to the surface).

Front

What is the unit of magnetic flux?

Back

The unit of magnetic flux is the Weber (Wb), which is equivalent to Tm² (Tesla meter squared).

Front

What is the definition of a Tesla?

Back

A Tesla (T) is the SI unit of magnetic flux density, defined as one weber per square meter (1 T = 1 Wb/m²).

Front

How do you calculate the magnetic flux through a circular loop?

Back

To calculate the magnetic flux (Φ) through a circular loop, use the formula: Φ = B * A * cos(θ), where B is the magnetic field strength, A is the area of the loop (A = πr² for a circular loop), and θ is the angle between the magnetic field and the normal to the loop.

Front

What is Lenz's law?

Back

Lenz's law states that the direction of the induced current (and emf) in a closed loop is such that it opposes the change in magnetic flux that produced it.

Front

What is the effect of decreasing magnetic field strength on induced emf?

Back

A decreasing magnetic field strength over time induces an emf in the opposite direction, according to Lenz's law. The magnitude of the induced emf is proportional to the rate of change of the magnetic field.