Force fields and electromagnets

Question 1

What does an atom consist of ?

Answer 1

A central nucleus, small electrons and equal positive and negative charges.

Question 2

Does and atom have a charge?

Answer 2

No they have no overall charge because negative and positive charges are equal.

Question 3

What happens when insulating materials are rubbed together?

Answer 3

The object gains electrons and a negative charge. The other object has a positive charge.

Question 4

What does a positively charged object attract?

Answer 4

Negative charged object

Question 5

What will two objects with the same charge do when together?

Answer 5

Repel

Question 6

What is the space around a charged object?

Answer 6

Electric field

Question 7

What does arrows on a diagram show?

Answer 7

The direction a positive charge would move

Question 8

What is resistance?

Answer 8

How easy or difficult it is for an electrical current to pass through a component

Question 9

What does the size of the current depend on?

Answer 9

The resistance and the voltage

Question 10

The higher the voltage…

Answer 10

The higher the current (if the resistance stays the same)

Question 11

The higher the resistance…

Answer 11

The lower the current (if the voltage stays the same)

Question 12

What does the resistance of a wire depend on?

Answer 12

The thickness (thicker wires have lower resistances), The length (longer wires have higher resistances), The material of which it is made from.

Question 13

What are the units for measuring resistance?

Answer 13

OhmsΩ

Question 14

How do you measure volts?

Answer 14

voltage = current × resistance

Question 15

How do you measure resistance?

Answer 15

resistance= current/voltage

Question 16

A bar magnet is a…

Answer 16

Permanent magnet, it is always magnetic and cannot be turned off. There are also two magnetic poles (north seeking and south seeking)

Question 17

What does a wire with electric flowing through it have?

Answer 17

A magnetic field

Question 18

What is an electromagnet ?

Answer 18

A wire coiled around that has an electric current running through it. It is only a magnet when electricity is running through it. The shape of the magnetic field is similar to a bar magnet.

Question 19

How do you make an electromagnet stronger?

Answer 19

Having an iron core, increasing the number of coils, increasing the current (by increasing voltage). Although there is a limit to how much current can be passed through it safely.

Question 20

What will happen when a wire carrying a current crosses a magnetic field?

Answer 20

The wire will experience a force called the motor effect

Question 21

What does an electric motor consist of?

Answer 21

A coil of wire in a magnetic field

Question 22

When there is a current in the coil of a motor what happens?

Answer 22

A force on each side of the coil makes it turn

Question 23

How do you increase the speed of the motor?

Answer 23

Increasing the size of the current, increasing the strength of the magnetic field, increasing the turns of wire on the coil

Question 24

What materials are magnetic?

Answer 24

Iron, nickel and cobalt (also steel is mostly iron so can be considered)

Question 25

How can you test if a piece of metal is actually a magnet?

Answer 25

Seeing if it repels a known magnet

Question 26

How do you detect a magnetic field?

Answer 26

Use a plotting compass or iron filings

Question 27

What force is a magnetic field?

Answer 27

non-contact force(doesn’t touch the magnet and material together)

Question 28

How do you draw a magnetic field diagram?

Answer 28

Draw the magnet, then draw the field lines that come out of the north pole and go into the south pole, make sure the field lines are more concentrated at the poles

Question 29

Where is the magnetic field strongest?

Answer 29

At the poles where the lines are the most concentrated.

Question 30

How does the earth behave?

Answer 30

As a giant magnet like one on a magnet. It also produces magnetic field which can be detected.

Question 31

What materials do you need for a simple motor?

Answer 31

two bar magnets, a coil of wire wrapped around something to support it, an axle for the coil of wire to spin around, two half rings