Magnetic effect of electric current 电流的磁效应

There is a magnetic field around after current passes through a wire.

• Most of the time

• Only when the current is strong

• True

• False

“Magnetic effect of electric current” is....

• magnetic fields generates a current around it.

• current generates a magnetic field around it.

• current generates a spinning field around it.

• current dont generates a magnetic field around it.

The right hand rule in a straight wire is...

• The right hand thumb indicates the direction of the current and the four fingers indicates the direction of the magnetic field.

• The left hand thumb indicates the direction of the current and the four fingers indicates the direction of the magnetic field.

• The right hand thumb indicates the direction of the magnetic field and the four fingers indicates the direction of the current.

• The right hand thumb indicates the direction of the sound signals and the four fingers indicates the direction of the magnetic field.

Explain the rightbhand rule with an easy drawing

The ------------ (1) the current is, the __________(2) the magnetism will be.

• (1) smaller

  (2) stronger

• (1) greater

  (2) weaker

• (1) faster

  (2) stronger

• (1) greater

  (2) stronger

By a simple drawing, what does the magnetic field of current look like?

Name the law in the picture.

• Voltage Law

• Current's Law

• Joule's Law

• Ampere's Law

The _____________ (1) away from the wire, the ______________(2) the magnetism will be.

• (1) farther

  (2) weaker

• (1) closer

  (2) weaker

• (1) farther

  (2) stronger

• (1) farther

  (2) faster

Explain a Relay.

• It is a magnetic switch.

• It is an Electromagnetic switch.

• It is an Electromagnetic field.

• It is a switch.

A Relay operates by.......

• a relatively shortl current

• a large current

• a relatively small current

• a relatively slow current