Physics yr9

Question 1

How can energy be stored

Answer 1

In a variety of different ways

Question 2

Name 4 different ways energy can be transferred

Answer 2

Heating, waves, electrical current or when an object is moved

Question 3

What happens when an object falls and gains speed

Answer 3

Its store of gravitational potential energy decreases and its kinetic energy store increases.

Question 4

What happens when a object hits the ground and it bounces back

Answer 4

Kinetic energy store increases

Question 5

Can energy be created or destroyed

Answer 5

No

Question 6

Does conservation of energy apply to all energy changes

Answer 6

Yes

Question 7

What is a closed system

Answer 7

A system in which no energy transfers take place out of or into the energy stores.

Question 8

Can energy be transferred between energy stores in a closed system

Answer 8

Yes

Question 9

What happens when an object moves up and down

Answer 9

Gravitational potential energy:
Increases when it moves up
Decreases when it moves down

Question 10

What happens when an object is lifted up

Answer 10

Gravitational potential energy store increases.

Question 11

Is the gravitational potential field strength at the moon’s surface less than on earth

Answer 11

Yes

Question 12

True or false
The energy in the kinetic energy store, depends on its mass and speed

Answer 12

True

Question 13

What energy is stored in an elastic object when work is done on it.

Answer 13

Elastic potential energy

Question 14

What is the name given to energy when it is in the place we want it and in the form we need it.

Answer 14

Useful energy

Question 15

What is the name given to the energy that is not useful and is transferred by an undesirable pathway

Answer 15

Wasted energy

Question 16

What happens when wasted energy is eventually transferred to the surroundings

Answer 16

It becomes warmer

Question 17

What happens as energy dissipates (spreads out)

Answer 17

It gets less and less useful

Question 18

True or false
An energy transfers can be more than 100% efficient

Answer 18

False

Question 19

What substances supply most of the energy we use in our house

Answer 19

Gas and/ or oil

Question 20

What is a wind turbine

Answer 20

An electricity generator on the top of a tall tower

Question 21

How do waves generate electricity

Answer 21

By turning a floating generator

Question 22

How does hydroelectricity generate energy

Answer 22

Generators are turned by water running downhill

Question 23

How does a tidal power station generate energy

Answer 23

Traps each high tide and uses it to turn generators.

Question 24

What are solar cells

Answer 24

Flat solid cells that use the suns energy to generate electricity directly

Question 25

How do solar heating panels heat water

Answer 25

Using the suns energy

Question 26

Where does geothermal energy come from

Answer 26

Energy transferred by radioactive substances deep inside the earth

Question 27

How do they produce steam to drive turbines

Answer 27

By pumping water into hot rocks

Question 28

Do nuclear fuels produce harmful waste

Answer 28

Yes

Question 29

How many cells does a battery consist of

Answer 29

Two or more

Question 30

What does the size of an electrical current =

Answer 30

Rate of flow of charge

Question 31

What is the equation for the electrical current of a circuit

Answer 31

I=Q/t

Question 32

How do you find potential difference across a circuit

Answer 32

V=E/Q

Question 33

How do you find the resistance

Answer 33

R=V/I

Question 34

What is ohms law

Answer 34

The current through a resistor at a constant temperature is directly proportional across its ends

Question 35

What are the characteristics for the components in a series

Answer 35

- the current is the same in each component - the total potential difference is shared between the components - adding their resistance gives the total resistance

Question 36

How do we find the total resistance

Answer 36

R total = R1+R2

Question 37

Does adding more resistors in series increases the total resistance

Answer 37

Yes

Question 38

What are the characteristics for the components in a parallel

Answer 38

- the total current is the sum of the currents through the separate components - the potential difference across each component is the same

Question 39

True or false The bigger the resistance of a component, the smaller the current that will pass through it

Answer 39

True

Question 40

What is the equation for the current through a resistor

Answer 40

I=V/R

Question 41

What happens if we add more resistors in a parallel circuit

Answer 41

The total resistance decreases