Electromagnetic Induction

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Electromagnetic Induction by Mind Map: Electromagnetic Induction

1. N = number of turns in coil

2. A = area of surface

3. .

3.1. where f = 1 / T

3.1.1. T = Period of revolution

3.2. AC Generator

3.2.1. Φ = NBAcosθ

3.2.1.1. BUT, θ = ωt

3.2.1.1.1. Hence, Φ = NBAcos ωt

4. Φ = Nϕ

5. Mother

6. ;.

6.1. Product of the magnetic flux density & the area normal to the field through which the field is passing

7. ∆Q = ∆Φ / R

8. Unit: Wb (Weber)

9. Φ = BAcosθ

10. induced emf as B parallel plane of disc and axis of rotation

11. .

11.1. copper disc rotates at frequency f between poles of magnet

12. Units of E: V (Volts of induced current)

13. .

14. l = length of conductor

15. Index - Magnetic Field Direction

16. The induced emf, E, in any closed circuit is equal to the time rate of change of the magnetic flux through the circuit

17. Direction of induced emf is such that it tends to oppose the flux-change causing it, and does oppose it if induced current flows

18. .

19. θ = angle between the magnetic field and the surface S

20. .

21. Magnetic flux ϕ

22. Magnetic flux linkage Φ

22.1. Total flux through the coil

22.2. Unit: Wb (Weber)

22.3. Φ = NBAcosθ

23. Q = NBA / R

23.1. R = total resistance of circuit

24. Faraday's Law

24.1. E <>< d/dt x (Nϕ)

24.2. Middle Finger - Induced Current Direction

24.2.1. Father

24.2.2. Child

25. Lenz's Law

25.1. E = - dϕ / dt

25.1.1. E = - N d(BAcosθ) / dt

25.1.2. Unit: V (Volts)

25.2. If this were not the case, magnet's velocity and KE would be increased indefinitely, but there is no source for the energy, so COE is violated

25.3. derived from Conservation of Energy

26. Fleming's Right Hand Rule

26.1. Thumb - Force Direction

26.2. B = magnetic flux density

27. Currents that are caused in metals moving in a magnetic field

27.1. can be +ve or -ve

28. EMF induced in Moving Straight Conductor

28.1. E = Blv

28.1.1. v = velocity

28.2. E = 0, when l or v is parallel to B

29. Applications of EMI

29.1. Use of search coil to measure flux density

29.2. Disc Generator

29.2.1. E = Bπr²f

29.3. Eddy Currents

29.3.1. Magnetic Effect

29.3.1.1. can be reduced by creating slots in the plate

29.3.1.1.1. Eddy currents cannot pass through air gaps

29.3.1.1.2. Use of search coil to measure B

29.3.1.2. Follow Lenz Law

29.3.1.2.1. oppose the motion producing them

29.3.2. Heating Effect

29.3.2.1. coil carrying high frequency ac, causes rapidly changing magnetic flux to induce large eddy currents

30. N pole induced in top of solenoid when magnet's North is moved towards solenoid to oppose direction of magnet

30.1. Use Right hand grip rule to determine direction of current

31. Note: If l or v is not perpendicular to the field lines

31.1. Component perpendicular to the field should be used