9j electricity (physics)

Question 1

What is inside an atom?

Answer 1

• a central nucleus
• electrons orbiting the nucleus
• protons and neutrons in the nucleus

Question 2

What happens when there is the same amount of electrons as protons in an atom?

Answer 2

It has no charge – it’s neutral.

Question 3

What is the charge of an electron, proton and neutron.

Answer 3

• an electron has a negative charge
• a proton has a positive charge
• a neutron has 0 charge (it’s neutral)

Question 4

What happens when you rub two materials together?

Answer 4

Electrons will be transferred from one material to the other, giving it a charge of static electricity. The material that loses electrons has a positive charge.

Question 5

Why can’t protons or neutrons be transferred from one material to another?

Answer 5

Because they are fixed inside the nucleus.

Question 6

What will happen with two opposite charges?

Answer 6

They will attract each other.

Question 7

What will happen with two of the same charges?

Answer 7

They will repel each other.

Question 8

Define an electric field.

Answer 8

The space around a charged object where it will attract or repel other charged objects.

Question 9

Define resistance.

Answer 9

How easy or difficult it is for an electric field to flow through it.

Question 10

If there is a higher voltage, what will happen to the current?

Answer 10

There will be a higher current (if the resistance stays the same)

Question 11

If there is a higher resistance, what will happen to the current?

Answer 11

There will be a lower current (if the voltage stays the same)

Question 12

Name 3 things the resistance of a wire depends on.

Answer 12

• the material it’s made from
• its length (longer wire = higher resistance)
• its thickness (thicker wire = lower resistance)

Question 13

Unit of measure for resistance.

Answer 13

ohms Ω

Question 14

Unit of measure for current.

Answer 14

amps A

Question 15

Unit of measure for voltage.

Answer 15

volts V

Question 16

Formula for resistance.

Answer 16

resistance = voltage / current

Question 17

A bar magnet is a…

Answer 17

permanent magnet

Question 18

A wire with electricity flowing through it has a…

Answer 18

magnetic field around it

Question 19

Electromagnet definition.

Answer 19

a coil of wire with an electric current flowing through it (it is only magnetic while the current is flowing)

Question 20

Name 3 ways an electromagnet can become stronger.

Answer 20

• increasing the number of coils on the wire
• increasing the size of the current (by increasing the size of the voltage)
• using an iron core

Question 21

Define the motor effect.

Answer 21

if a wire carrying a current crosses a magnetic field, the wire will experience a force

Question 22

What does a motor consist of?

Answer 22

a coil of wire in a magnetic field

Question 23

What happens when there is a current in the coil?

Answer 23

There is a force on each side of the coil that makes it turn

Question 24

Name 3 ways a motor’s speed (or the force it provides) increases.

Answer 24

• increase the size of the current
• increasing the strength of the magnetic field
• increasing the number of turns of wire on the coil