Електромагнетна индукција Индукована ЕМС – проблеми и решења

3 Electromagnetic induction Induced EMF – Problems and Solutions

1. A coil replaced with another coil that has loops 2 times the initial loops and the rate of change of magnetic flux is constant. Determine the ratio of initial and final induced emf.

Познато:

Initial loops (N) = 1

Final loops (N) = 2

The rate of change of initial magnetic flux (ΔØ_B / Δt) = the rate of change of final magnetic flux (ΔØ_B / Δt)

Трази се: The ratio of initial and final induced emf

Решење:

The equation of Faraday’s law of induction :

E = -N (ΔØ_B / Δt)

E = induced EMF, N = number of loops, ΔØ_B / Δt = the rate of change of magnetic flux

The ratio of initial and final induced emf :

E initial: E final

-N (ΔØ_B / Δt) : -N (ΔØ_B / Δt)

КСНУМКС: КСНУМКС

2. In the initial state (1), the magnetic flux is changed by 5 Wb in 2 seconds on a coil with 20 loops. In the final state (2), the same flux changed in 8 seconds. Determine the ratio of the initially induced emf and the final induced emf.

Познато:

The rate of change of initial magnetic flux (ΔØ_B / Δt) = 5/2

The rate of change of final magnetic flux (ΔØ_B / Δt) = 5/8

Number of loops (N) = 20

Трази се: The ratio of the initially induced emf and the final induced emf

Решење:

E initial: E final

-N (ΔØ_B / Δt) : -N (ΔØ_B / Δt)

20 (5/2) : 20 (5/8)

5/2: 5/8

1/1: 1/4

КСНУМКС: КСНУМКС

3. The magnetic flux of the initial coil has 200 loops changes by 0.06 Wb in 0.4 seconds. The magnetic flux of the final coil has 0.08 Wb in 0.2 seconds. If several loops of the final coils are substituted with the half number of the first coil’s loops, determine the ratio of the induced emf of the initial loops and the final loops.

Познато:

The rate of change of initial magnetic flux (ΔØ_B / Δt) = 0.06 / 0.4

Number of initial loops (N) = 200

The rate of change of final magnetic flux (ΔØ_B / Δt) = 0.08 / 0.2

Number of final loops (N) = 100

Тражи се: The ratio of the initial induced emf and the final induced emf

Решење:

E initial : E final

-N (ΔØ_B / Δt) : -N (ΔØ_B / Δt)

200 (0.06/0.4) : 100 (0.08/0.2)

2 (0.15) : 1 (0.4)

0.3 : 0.4

3 : 4