Magnetism And Electromagnetism(p)

Question 1

What are magnets?

Answer 1

Any material/object that produces a magnetic field

Question 2

What are examples of magnets?

Answer 2

Bar magnet
Earth
Horse shoe magnet

Question 3

What are the field lines on a magnet?

Answer 3

Mines drawn around a magnet connecting North Pole to South Pole

Question 4

What are the direction of arrows at different poles?

Answer 4

Arrows out at north and in at south

Question 5

What happens when two of the same poles are together?

Answer 5

Repulsion takes place from the indirection of the magnetic fields

Question 6

How is the strength of magnetic fields shown?

Answer 6

By the the density of the field lines

Question 7

What are permanent magnets?

Answer 7

Produce there own magnetic field all the time

Question 8

What are induced magnets?

Answer 8

Only have magnetic fields temporarily (always attractive to permanent magnets)

Question 9

What magnetic materials lose and gain magnetism quickly ?

Answer 9

Soft materials

Question 10

What materials gain and lose magnetism slowly?

Answer 10

Hard materials

Question 11

What happens when an electrical current, flows through a material?

Answer 11

A magnetic field is always produced

Question 12

What is a an electromagnet?

Answer 12

Electric current produces there own magnetic field. Solenoid with iron core

Question 13

What happens when the current for an electromagnet is switched off??

Answer 13

Electromagnet disappears

Question 14

How do you increase strength of electromagnet?

Answer 14

-increase current
-increase number of turns in solenoid(same length)
reduce length of solenoid (same turns)
-add soft iron core

Question 15

What is the motor affect?

Answer 15

A wire carrying current in the presence of a magnetic field will experience a force

Question 16

How do you calculate the strength of the force?

Answer 16

F=BxIxL

Forcé (n)= magnetic flux density (t)x current (a)x length of wire(m)

Question 17

What is an electric motor?

Answer 17

-change direction of current every half turn.
Which makes the coil continue to rotate in same direction
(As the current flow in positive terminal into negative terminal)

Question 18

What is the split ring commutator used for in electric motor?

Answer 18

-swaps positive and negative connections every half turn. So directions of current swaps every half turn

Means forces acting on the coil will always act in same direction

Question 19

How do you increase rotation of the electric motor?

Answer 19

-increase current in coil
-increase magnetic flux density of magnet
-add more turns to coil

Question 20

Why are certain materials, like paper clips attracted to magnets!

Answer 20

They are made of magnetic materials. So they become induced to magnet

Question 21

What evidence shows magnetic field of earth has changed?

Answer 21

Changing position of magnets north and south

Question 22

What part in earth which movement takes place?

Answer 22

Outer zone