Physics

Question 1

How does heat energy move?

Answer 1

From hot object and areas to cold objects and areas

Question 2

How do you measure heat in a substance

Answer 2

Checking its temperature

Question 3

How can energy be transferred

Answer 3

Through conduction in solids and liquids, convection in liquids and gasses and through radiation in space.

Question 4

Explain the process of conduction

Answer 4

Conduction is the process by which heat energy is transmitted through collisions between neighbouring atoms or molecules. Conduction occurs more readily in solids and liquids where particles are closer together than in gases where particles are further apart. For example in a cup of coffee, energy is trandered by heating from the bottom of the mug to the table on which the mug is.

Question 5

Explain how convection occurs

Answer 5

Convection works by areas of a liquid or gas heating or cooling greater than their surroundings causing differences of temperature. The hotter less dense areas rise and the cooler more dense areas sink. For example in a mug of hot coffee heating from the surface of the coffee evaporates setting up a convention current.

Question 6

Explain how energy is transferred by radiation

Answer 6

It emits electromagnetic waves.

Question 7

Explain the effect of surface area, colour and degree of lustrous mess on the absorption and emission of radiation

Answer 7

The color of an object affect how well it emits and absorbs thermal radiation/ black colour are the bests emitting and absorbing radiation. Shiny objects are the worst emitting and absorbing

Question 8

State 8 types of energy

Answer 8

Kinetic
Electrical
Chemical

Thermal
electromagnetic
Nuclear
Sound
Elastic

Question 9

What are the four main ways or transferring energy?

Answer 9

Mechanically, by heating, electrically and by light and sound

Question 10

Explain the types of fossil fuels and explain which ones contain more energy

Answer 10

The three most important fossil fuels are coal, petroleum and gas natural. Natural gas (hydrogen) fuel contains the most energy.

Question 11

How is energy released from fuels?

Answer 11

By burning them

Question 12

What is the difference between renewable and non-renewable energy sources?

Answer 12

Renewable energy resources are natural sources that can be replenished at a higher rate than they are consumed. As a result they will not run out. Non-renewable resources take hundreds of millions of years to forms.

Question 13

Explain the stages in which energy is generated in power plants

Answer 13

Power plants generate electricity through various technologies.
1. Water in the boiler is heated turning it into steam
2. Steam generated by the boiler will make the turbines spin. This is connected by the driveshaft to the generator which spins creating an electrical current.
3. The steam rises from the turbine to the cooling towers
4. Steam cools down converting back to a liquid state (water).
5. Water falls back down to the boiler completing the cycle.

Question 14

Describe some examples the process for harnessing renewable energy

Answer 14

Solar Energy: Solar panels can be installed on rooftops and in large solar farms to capture the energy from the sun and convert it into electricity.

Wind Energy: Wind turbines can be installed in areas with strong winds, such as onshore and offshore wind farms, to generate electricity.

Hydropower: Hydroelectric power plants can be built on rivers and other bodies of water to generate electricity from the movement of water.

Geothermal Energy: Geothermal power plants can be built in areas with high underground temperatures to harness the heat and generate electricity.

Biomass Energy: Biomass, such as wood chips and agricultural waste, can be burned to produce heat and electricity.

Question 15

Why do we need to use renewable energy sources over non-renewable?

Answer 15

Generating energy that produces no greenhouse gas emissions from fossil fuels and reduces some types of air pollution
Non - renewable energy is replaced much faster than it is consumed.

Question 16

Explain how energy is transferred from power plant to the home

Answer 16

Power plants generate electricity that is delivered to customers. This is through the generator which creates an electrical current which goes to the national grid. The structure connects to our homes via power lines - supplying houses with the required electricity.

Question 17

How do you measure energy usage at home?

Answer 17

Power tells you how fast something transfers energy. It’s usually measured in watts (W) or kilowatts (kW). 1 kW = 1000 W. The total amount of energy transferred by an appliance depends on the amount of time that it’s switched on for and its power. If you know the power in Kilowatts and the time in hours, you can calculate energy transferred using this equation:

Energy transferred (kWh)= power (kW) * time (h)

Electricity meters record the amount of energy transferred in kWh.

Question 18

How are electricity bills calculated?

Answer 18

COST = Energy transferred (kWh) × PRICE per kWh

Question 19

Explain why we experience day and night on Earth

Answer 19

1) The Earth does one complete rotation in 24 hours. That’s what a day actually is — one complete rotation of the Earth about its axis. 2) The Sun doesn’t really move, so as the Earth rotates, any place on its surface will sometimes face the Sun (day time) and other times face away into dark space (night time).

Question 20

Explain why we experience seasons on Earth

Answer 20

The Earth takes 365 ¼ days to orbit once around the Sun. The seasons are caused by the tilt of the Earth’s axis.

When it’s summer in the UK, the northern hemisphere (everything above the equator) is tilted towards the Sun. The northern half of the Earth spends more time in sunlight than it does in darkness, i.e. days are longer than nights. Longer days mean more hours of sunshine — so the land heats up. Not only that, but the Sun’s rays cover a small area of land. This means that the energy they transfer is focused on a small area.

1) When it’s winter in the UK, the northern hemisphere is tilted away from the Sun. 2) The north now spends less time in sunlight, so days are shorter than nights. 3) Also, the Sun’s rays cover a larger area of land, so the energy they transfer is more spread out. So it gets colder.

Question 21

Explain how solar eclipses happen

Answer 21

A solar eclipse happens when the Moon passes between the Sun and Earth, blocking at least some of the Sun and casting a shadow on Earth.

Question 22

Explain how lunar eclipse happens

Answer 22

A Lunar eclipse occurs when the Sun casts Earth’s shadow onto the Moon. For this to happen, the Earth must be physically between the Sun and Moon with all three bodies lying on the same plane of orbit. A lunar eclipse can only occur during a Full Moon and when the Moon passes through all or a portion of Earth’s shadow.

Question 23

How long does it take the moon to orbit the Earth?

Answer 23

28 days

Question 24

Why the moon appears differently in the sky over a month?

Answer 24

The Moon doesn’t emit (give off) light itself, the ‘moonlight’ we see is actually the Sun’s light reflected off the moon.
So, as the Moon orbits the Earth, the Sun lights up different parts of it, making it seem as if the Moon is changing shape.

Question 25

State the order of the 8 planets in the solar system

Answer 25

Mercury
Venus
Earth
Mars
Jupiter
Saturn
Uranus
Neptune

Question 26

Explain the difference between weight and mass

Answer 26

Mass is a fundamental measurement of how much matter an object contains. Weight is a measurement of the gravitational force on an object. It not only depends on the object’s mass, but also on its location.

Question 27

What is the formula for calculating weight?

Answer 27

W=m*g

“W” is the weight of the object, “m” is the mass of the object, and “g” is the gravitational field strength.

Question 28

State the forces that act on rockets as they leave earth

Answer 28

These three forces affect a rocket inflight: thrust.gravity,and drag.

Thrust
Thrust is the force generated by arocket engine that propels the rocket.Thrust must be greater than the pull ofgravity for a rocket to fly upwards.

Gravity
Gravity is the downward force appliedto all objects on earth. More force isrequired to lift a heavy rocket than alight rocket.The heavier the rocket,themore thrust required to lift the rocketinto space.

Drag
Drag is the amount of air resistanceor friction on the rocket as it flies.Dragis minimized by reducing the frontal sur-face area of the rocket and by having asmooth exterior finish.If two rockets ofsimilar size and weight were launchedwith the same force,the rocket with thelowest drag would fly farther.

Question 29

How can rockets make it into space

Answer 29

Oxígen is needed for engines to work and there is no oxígen in space. Unlike jet engines, rocket engines do not get oxygen from the air. Instead, they carry their own oxygen with them.

Similar to an aircraft’s jet engine, rocket engines work by shooting very hot gas out from the back of the rocket. As the gas is pushed backwards, the rocket is pushed forward.

This is an example of the Third Law of Motion. This law says that every action has an equal and opposite reaction.

Question 30

Why does conduction happen most readily in solids and liquids?

Answer 30

The atoms and molecules and closer together.

Question 31

How is heat energy transferred by radiation?

Answer 31

Radiation heat transfer occurs via electromagnetic waves.

Question 32

Why can heat energy transferred by radiation occur in a vacuum?

Answer 32

Because radiation involves electromagnetic waves, not particles.

Question 33

What is meant by the term ‘solar system?’

Answer 33

A solar system is a group of planets and other bodies that revolve around a star.

Question 34

Why do different bodies have different gravitational field strengths?

Answer 34

Because the gravitational field strength of a body depends upon its size, mass and density.

Question 35

Why do the planets orbit the sun?

Answer 35

Planets orbit a sun because the sun’s gravity is stronger than any planet’s so it pulls the planets towards it.

Question 36

Why do moons orbit around planets?

Answer 36

Moons orbit around planets because the planet’s gravity is greater than that of the moon so the moon is pulled towards it.

Question 37

What is the formula for energy transferred ?

Answer 37

Force (newtons) X distance (metres)