7Electromagnetic_induction_DC_generator_and_an_electric_engine_presentation

  • ppt
  • 07.05.2020
Публикация на сайте для учителей

Публикация педагогических разработок

Бесплатное участие. Свидетельство автора сразу.
Мгновенные 10 документов в портфолио.

Иконка файла материала 7Electromagnetic_induction_DC_generator_and_an_electric_engine_presentation.ppt

Faraday's law and Lentz’s law-Application

Learning objectives

-to explain the received results in a well-argued manner using Faraday's law of induction and Lentz's law.
-apply Faraday’s and Lentz’s law in action

Electromagnetic Induction-Investigation

Faraday’s Law of Induction

A changing magnetic flux induces an EMF

Questions-Answers method

Why current do induced in the circuit?
How do you name this current?
How to determine the direction of induced current?
Why current is induces when only magnet is in action?

5

What is EMF?

Looks like potential. It’s a “driving force” for current

Faraday’s Law of Induction

A changing magnetic flux induces an EMF, a curling E field

Magnetic Flux Thru Wire Loop

Analogous to Electric Flux (Gauss’ Law)

(1) Uniform B

(2) Non-Uniform B

Minus Sign? Lenz’s Law

Induced EMF is in direction that opposes the change in flux that caused it

10

Faraday’s Law of Induction

Changing magnetic flux induces an EMF

Lenz: Induction opposes change

Ways to Induce EMF

Quantities which can vary with time:

Magnitude of B
Area A enclosed by the loop
Angle q between B and loop normal

12

Technology

Many Applications of Faraday’s Law

13

Metal Detector

14

Induction Stovetops

15

Ground Fault Interrupters (GFI)

16

Electric Guitar

Pickups

17

Electric Guitar