PHY

Question 1

What is the particle theory of matter?

Answer 1

all matter is made up of particles and these particles are always moving

Question 2

Define conduction

Answer 2

the energy transfer from one object to another by direct contact

Question 3

Define convection

Answer 3

the transfer of thermal energy through the movement of particles from one location to another

Question 4

How do we reduce convection and give and example

Answer 4

Stop the free flow of fluids e.g. sleeping under a blanket which stops warm air from escaping

Question 5

Define radiation

Answer 5

the energy that is emitted by matter in the form of photons or electromagnetic waves

Question 6

What is radiation energy carried by?

Answer 6

infrared rays

Question 7

Define internal energy

Answer 7

the total energy stored by particles making up a substance or a system

Question 8

Define specific heat capacity

Answer 8

the amount of energy needed to raise the temperature of 1kg of a substance

Question 9

Define Latent heat and what 2 things does it depend on?

Answer 9

the amount of energy required to change the state of 1kg of a substance

depends on the type of substance and the amount of the substance

Question 10

Define latent heat of vaporisation

Answer 10

energy change when a substance changes between a liquid + gas

Question 11

Define latent heat of fusion

Answer 11

Energy change when a substance changes between a solid + liquid

Question 12

Define power

Answer 12

the measure of the rate of heat energy absorbed or released when a substance changes temperature or state

Question 13

Define waves

Answer 13

Transfer of energy from one place to another without transferring matter

Question 14

Elements of longitudinal waves

Answer 14

Oscillations are perpendicular to the direction of energy transfer

Needs particles

Can travel through solid + liquids + gases but not vacuum

Speed is 340 ms-1

Speeds up more in a dense medium

Question 15

Elements of transverse waves

Answer 15

Oscillations that are parallel to the direction of energy transfer

Doesn’t need particles

Can travel through gases + transparent solids + liquids + vacuum

Speed is -3x10^8 ms-1

Slows down in a more dense medium

Question 16

What type of waves are electromagnetic waves

Answer 16

Transverse

Question 17

What speed are all electromagnetic waves when in a vacuum?

Answer 17

3x10^8 ms-1

Question 18

What happens when electromagnetic waves speed when they enter a different medium?

Answer 18

They all travel at different speeds, which can lead to refraction - where the waves change directions

Question 19

What happens to wavelength when frequency goes up?

Answer 19

Wavelength decreases

Question 20

What happens to wavelength when frequency goes down?

Answer 20

Wavelength increases

Question 21

Order the types of electromagnetic waves from left to right

Answer 21

Radio waves - micro waves - infrared - visible light - ultra violet - xrays - gamma rays

Question 22

Define law of reflection

Answer 22

When a ray of light is reflected off a surface, angle of incidence equals the angle of reflection

Question 23

Define refraction

Answer 23

The bending of light rays when they enter from one medium to another medium

Question 24

What happens to a wave when it travels to a more dense medium

Answer 24

bends TOWARDS the normal (slower)

Question 25

What happens to a wave when it travels to a less dense medium

Answer 25

bends AWAY from the normal (faster)

Question 26

Define diffraction

Answer 26

Bending of waves through a gap or around a barrier

Question 27

What would happen if the slit is larger/smaller than the gap between the waves?

Answer 27

If the slit was larger, the waves would not be bent as much as the above diagram. Slit width and wavelength both affect the amount of diffraction. So, with wavelength staying the same, but slit width increasing, the amount of diffraction will decrease.

Question 28

What happens during total internal reflection?

Answer 28

Light is moving from a more dense medium towards a less dense medium. Occurs when the angle of incidence is greater than the critical angle. Light is reflected, not refracted.

Question 29

Describe the process of total internal reflection

Answer 29

TOTAL INTERNAL REFLECTION occurs depending on if the angle of incidence is greater than the critical angle. If the angle of incidence is less than the critical angle, then most of the light passes out, but a little bit is internally reflected. As you increase the angle of incidence, more light gets internally reflected, unless light is refracted out. Once the angle of incidence is greater than the critical angle, no light is refracted and all of the light is internally reflected, creating internal reflection.

Question 30

What is the equation for finding the critical angle?

Answer 30

n1sin0c = n2sin90

Question 31

What is the critical angle

Answer 31

The angle of incidence that gives us an angle of refraction of 90 degrees

Question 32

Define magnet

Answer 32

any material or object that produce a magnetic field

Question 33

What do all magnets have?

Answer 33

A north and south pole and have a magnetic field surrounding them

Question 34

How can we tell how strong the magnetic field is?

Answer 34

The closer the field lines are, the stronger the magnetic field in that area.

Question 35

How do we draw field lines around a bar magnet?

Answer 35

Lines going into the south lines coming out of north lines that loop all the way from north to south

Question 36

Define electromagnetism

Answer 36

Where electric currents produce their own magnetic fields

Question 37

How can we remember which direction field lines go?

Answer 37

Right hand rule

Question 38

What are two elements of a solenoid

Answer 38

strong and uniform

Question 39

A solenoid is an example of a what?

Answer 39

electromagnet

Question 40

What are 4 things we can do to increase electromagnetic strength

Answer 40

1. Increase current that flows through solenoid 2. Increase the amount of turns in our coils while keeping length the same 3. Decrease the length of the coil while keeping the number of turns the same 4. Add an iron core inside of the solenoid

Question 41

Why will electromagnetic strength of a solenoid increase when an iron core is added?

Answer 41

Iron is a soft magnetic material, therefore it will become an induced magnet when the solenoid is switched on, which massively increases the strength of the magnetic field.

Question 42

What is hydroelectric energy?

Answer 42

A renewable energy source that generates electricity by using the kinetic energy of flowing water, typically through dams or water control structures that direct water through turbines to produce power.

Question 43

What is an advantage of hydroelectric energy

Answer 43

It is a renewable, environmentally friendly energy source that generates power steadily and produces no carbon emissions.

Question 44

What is a disadvantage of hydroelectric energy?

Answer 44

Dams can harm the environment upstream and downstream by disrupting habitats during construction and through new infrastructure like roads and power lines. Additionally, building a dam is expensive.

Question 45

What is wind energy?

Answer 45

Wind turbines harness the wind's energy and convert its kinetic energy into electricity.

Question 46

What is an advantage of wind energy

Answer 46

Wind energy is a clean, renewable source that generates electricity without emitting greenhouse gases or pollutants. Since wind is constant, its energy can always be harnessed. Wind turbines produce some of the cheapest electricity available.

Question 47

What is an disadvantage of wind energy

Answer 47

Can be unreliable, as it depends on wind availability. Turbine blades can be noisy, affecting residents and wildlife. Birds and bats are also at risk of being killed by flying into the blades.

Question 48

What is geothermal energy?

Answer 48

Heat extracted from the Earth's crust. Geothermal power plants pump high-pressure fluids from underground. When the water reaches the surface, pressure drops, turning it into steam that drives turbines connected to a generator to produce electricity.

Question 49

What is an advantage of geothermal energy

Answer 49

Geothermal energy is a renewable, environmentally friendly alternative to fossil fuels. It has a low carbon footprint and provides a more reliable energy source compared to wind and solar power.

Question 50

What is an disadvantage of geothermal energy

Answer 50

One disadvantage: Its location-specific nature, as plants must be built where energy is accessible. It also carries risk of triggering earthquakes due to changes in the Earth’s structure from drilling. Additionally, geothermal energy is costly to utilize.

Question 51

What is solar energy?

Answer 51

Solar power is energy harnessed from the sun's radiation. Solar panels, typically made of photovoltaic cells, capture sunlight and convert it into electricity.

Question 52

What is an advantage of solar energy

Answer 52

Solar power is renewable, making it a sustainable energy source. It reduces electricity bills and has a low environmental impact since it doesn't emit harmful pollutants.

Question 53

What is an disadvantage of solar energy

Answer 53

Solar power is weather-dependent and less efficient on cloudy or rainy days. Installation cost a lot Manufacturing and disposal of solar panels can have environmental impacts.

Question 54

What are transformers used for?

Answer 54

used to increase or decrease the voltage of alternating currents

Question 55

What are three things a transformer is consisted of?

Answer 55

A primary coil, a secondary coil and an iron core

Question 56

What does a step up transformer do in terms of voltage and current

Answer 56

steps-up voltage, steps-down current

Question 57

What does a step down transformer do in terms of voltage and current

Answer 57

steps-down voltage, steps-up current

Question 58

What does the output of voltage in a transformer depend on (2 things)

Answer 58

input voltage and the ratio of turns on the coil

Question 59

Define fission

Answer 59

the nuclear reaction whereby large nuclei are induced to break up into smaller nuclei and release energy in the process.

Question 60

Describe the process of fission

Answer 60

A typical single reaction might involve bombarding a uranium nucleus with a neutron. This can cause the uranium nucleus to break up into two smaller nuclei. This releases a large amount of energy in the form of heat and radiation.