D.4 Induction HL

Question 1

Magnetic Flux (Symbol)

Answer 1

φ (Phi) - Represents the total number of magnetic field lines passing through a given area, measured in Webers (Wb)

Question 2

Magnetic Field Strength (Symbol)

Answer 2

B - Measures the intensity of a magnetic field in a given area, expressed in Teslas (T).

Question 3

Magnetic Field Lines

Answer 3

Represent the direction and strength of a magnetic field; closer lines indicate a stronger field

Question 4

Equation for Magnetic Flux

Answer 4

φ = BA cos θ - Where φ is the magnetic flux, B is the magnetic field strength, A is the area through which the field lines pass, and θ is the angle between the field lines and the normal to the surface.

Question 5

Magnetic Flux Density

Answer 5

Represents how close together the field lines are, indicating the strength of the magnetic field. Measured in Teslas (T) or Webers per square meter (Wb/m^2).

Question 6

Factors Affecting Magnetic Flux

Answer 6

The amount of magnetic flux through a surface depends on the strength of the magnetic field (B), the area of the surface (A), and the angle (θ) between the field lines and the normal to the surface

Question 7

Faraday’s Law of Induction

Answer 7

States that the induced electromotive force (emf) in any closed circuit is equal to the negative of the time rate of change of the magnetic flux through the circuit.

Question 8

Formula for Induced emf

Answer 8

ε = -N(ΔΦ/Δt) where ε is the induced emf, N is the number of turns in the coil, ΔΦ is the change in magnetic flux, and Δt is the time interval.

Question 9

Lenz’s Law

Answer 9

The direction of an induced emf is such that it opposes the change in magnetic flux that produced it, reflecting the conservation of energy.

Question 10

Condition for Maximum emf Induction

Answer 10

The maximum emf is induced when a conductor moves perpendicularly to the magnetic field lines, maximizing the change in magnetic flux.

Question 11

Relationship Between emf, Magnetic Field Strength (B), Velocity (v), and Length (L)

Answer 11

ε = BvL, where ε is the induced emf, B is the magnetic field strength, v is the velocity of the conductor, and L is the length of the conductor within the magnetic field.

Question 12

Significance of Negative Sign in EMF Equation

Answer 12

Indicates that the induced EMF works to oppose the change in magnetic flux through a circuit.

Question 13

Direction of Induced Current

Answer 13

Determined by Lenz’s Law; it opposes the change in magnetic flux that induced it.

Question 14

Conservation of Energy in EMF Induction

Answer 14

Lenz’s law ensures the conservation of energy by opposing the change that causes induced EMF.

Question 15

Application of Lenz’s Law in Technology

Answer 15

Used in electromagnetic braking and induction charging, exploiting the opposition of induced currents to change in magnetic flux.

Question 16

Principle of AC Generation

Answer 16

AC electricity is produced by rotating a coil within a magnetic field, inducing an EMF that oscillates sinusoidally.

Question 17

Effect of Coil Rotation Speed

Answer 17

Faster rotation speeds increase the frequency and magnitude of the induced EMF due to a quicker rate of magnetic flux change

Question 18

Sinusoidal EMF Induction

Answer 18

The EMF output oscillates sinusoidally over time when a coil rotates in a constant magnetic field, producing alternating current (AC).

Question 19

Role of Magnetic Field Strength

Answer 19

Increasing the magnetic field strength within which the coil rotates enhances the induced EMF

Question 20

Nikola Tesla and AC Electricity

Answer 20

Tesla advocated for AC electricity due to its ability to be transmitted over longer distances efficiently, showcasing the practical application of AC generators.