Physics Paper 1 Topics Flashcards
What are the 8 energy stores?
the 8 energy stores are kinetic, gravitational potential,
elastic potential, electrostatic, thermal, chemical,
magnetic, nuclear
What are the 4 types of energy transfers?
The four types of energy transfers include mechanical,
electrical, heating, radiation
What is a system?
A system is a single object or a group of objects
Describe the energy transfers when an arm throws a ball up
Energy stored in chemical energy store of arm > force
exerts by arm doing work > kinetic energy store of the ball and arm
Describe the energy transfers when a ball is falling
Gravitational potential energy store of ball >
gravitational fall force work > kinetic energy store of the
ball
Describe the energy transfers of a car applying their
brakes
Kinetic energy store of wheels > friction does work >
thermal energy store of surroundings
Describe the energy transfers when a car hits a tree
Kinetic energy store of car > normal contact force
does work > other energy stores eg elastic potential
energy store
Describe the energy transfers of a kettles heating
element + water
Switch > energy transferred electrically > kettles
thermal energy store > energy transferred by heating >
thermal energy store of water
How do we calculate kinetic energy?
Kinetic energy = 1/2 x mass x velocity squared
How do we calculate gravitational potential energy?
Gravitational potential energy = mass x gravitational field strength x height
What is the conservation of energy?
The conservation of energy states that energy can be transferred usefully, stored or dissipated but not created or destroyed
What is specific heat capacity?
Specific heat capacity is the amount of energy needed to raise 1kg of a substance by 1 degree celcius
What is a closed system?
A closed system is when no energy or matter is transferred in or out of the system, so there is no overall change in total energy
How is energy transferred through a pot on a hob?
Energy is transferred usefully to thermal energy store, some energy is dissipated to thermal energy store of surroundings
What is conduction?
Conduction is a process where vibrating particles transfer energy to neighbouring particles
What is convection?
Convection is where energetic particles move from hotter to cooler regions
What are two ways we can reduce unwanted energy transfers and how do they work?
We can reduce unwanted energy transfers with lubricants and thermal insulation. Lubricants reduce frictional force therefore less energy is dissipated. Thermal insulation eg wool reduces unwanted energy transfers by heating
How can we decrease how quickly a building cools?
We can decrease how quickly a building cools by increasing the thickness of the walls and making the walls out of material with lower thermal conductivity.
What does a higher thermal conductivity mean?
Higher thermal conductivity means energy is transferred faster by conduction
What is the independant and dependant variable involved when you are finding the affect of different materials on the mass of hot water?
Independant variable = type of material of material thickness
Dependant variable = temperature change > measure with thermometer and timer
How is electricity transferred across the national grid?
In the national grid, electricity is transferred from the power station > step up transformer > step down transformer > consumer
What does a step up transformer do?
Step up transformer increases potential difference and decreases current
What does a step down transformer do?
Step down transformer decreases potential difference and increases current
How can we increase the effiency of energy transfer in the national grid?
Increase efficency by decreasing current and increasing potential difference, as a high current means that the wires will heat up and transfer a lot of energy to the thermal energy store of surroundings
What is the method for determing the density of a regular solid?
Use balance to find mass > use ruler to find length of each side > calculate volume by cubing the length > density = mass/volume
What is the method for determing the density of an irregular solid?
Use balance to find mass > fill eureka can with water > place object in water so water is displaced and flow out > measure volume of water displaced > density = mass/volume
How do you calculate density?
Density = mass/volume
What are the features of a solid? (arrangement, forces, distance, motion)
Solids:
- Fixed arrangement
- Strong forces between particles
- Close together
- Vibrates
What are the features of a liquid? (arrangement, forces, distance, motion)
Liquids:
- Irregular particle arrangement
- Weak forces between particles
- Small distance between particles
- Slow particle motion
What are the features of a gas? (arrangement, forces, distance, motion)
Gas:
- Irregular particle arrangement
- Very weak forces between particles
- Far apart from each other
- Fast particle motion
What happens during boiling/heating? (when they change state)
During boiling:
- Bonds are broken
- Internal energy increases
- Temperature stays the same
What happens during freezing/condensing? (when they change state)
During freezing/condensing:
- Bonds strengthen
- Internal energy decreases
- Temperature stays the same
What is specific heat capacity?
Specific heat capacity is the amount of energy needed to raise the temperature of 1kg of a substance by 1-degree Celcius
What is specific latent heat?
Specific latent heat is the amount of energy needed to change 1kg of a substance from one state to another without changing its temperature
How do we increase the effeciency of an object being heated eg a pot on a hob or a kettle?
Increase effeciency by placing the heating element in the water, adding a lid, using plastic walls to reduce heat escaping through walls as plastic has a low thermal conductivity
Why do solids have a high density?
Solids have a high density because the particles are close together, meaning it has a lot of mass for its volume
Why do gases have a low density?
Gases have a low density because particles are far apart, and has a small mass for their volume
Why do some solids have a lower density than others?
Solids that are an open structure with open spaces have a lower density
What is the change of state called when a solid becomes a gas?
When a solid becomes a gas, this is called sublimation
What are the energy transfers involved when an arm throws a ball up?
Chemical energy store of arm > force exerted by arm doing work > kinetic energy store of ball and arm
What are the energy transfers of a ball falling?
Gravitational potential energy store of ball > gravitational force does work > kinetic energy store of ball
What are the energy transfers of brake applying to car wheels?
Kinetic energy stores of wheels > friction does work > thermal energy store of surroundings
What are the energy transfers of a car hitting a tree?
Kinetic energy store of car > normal contact force does work > other energy stores eg elastic potential
What are the energy transfers of a kettles heating element and water?
Switch > energy transferred electrically > thermal energy store of kettles heating element > energy transferred by heating > thermal energy store of water
What are the trends in energy use between 1990s and 2000s?
Between the 1990s and 2000s, electricity increased due to population growth
What are the trends in energy use after the 2000s?
After the 2000s, electricity use decreases as appliances become efficient
Why do we advocate for more renewable energy?
None-renewable energy is damaging to the environment, and will eventually run out
What happens in an ohmic conductor? (at constant temperature)
In an ohmic conductor, the current is directly proportional to potential difference so resistance doesn’t change. The IV characteristic is linear
What happens in a filament lamp?
In a filament lamp, current increases, temperature increases and so resistance increases. The IV characteristic is non-linear.
What happens in a diode?
In a diode, there is high resistance in one direction, and current only flows in the other direction. The IV characteristic for a diode is non-linear.
What happens in an LDR?
In an LDR:
- Resistance depends on light intensity
- Lower resistance in bright light
- Used in automatic night lights
What happens in a thermistor?
In a thermistor:
- Resistance depends on temperature
- Lower resistance in higher temperature
- Used in thermostats
What does the amount of energy an appliance transfers depend on?
The amount of energy an appliance transfers depends on:
- Appliance’s power
- How long appliance is on for
How is an electric spark formed?
Electric charge builds up on an object, potential difference between object and earth increases, when potential difference is large enough there is a spark
How does a static charge form?
Two materials rub together, electrons move from one to another, materials become electrically charged, charge is equal and opposite
What happens when a substance melts/boils?
When a substance melts/boils:
- Bonds are broken
- Internal energy increases (energy is transferred to particles’ potential energy store)
- Temperature stays the same
What happens when a substance condenses/freezes?
When a substance condenses/freezes:
- Bonds strengthen
- Internal energy decreases (energy transferred away from particles potential energy store)
- Temperature stays same
What is the specific latent heat of fusion?
Specific latent heat of fusion is the specific latent heat of changing between a solid and liquid
What is the specific latent heat of vapourisation?
Specific latent heat of vapourisation is the specific latent heat of changing between a liquid and a gas
Why is an atom’s overall charge zero?
An atom’s overall charge is zero because number of electrons = number of protons
How are electrons and EM radiation related?
Electrons absorb EM radiation to move to higher energy levels, and emit EM radiation to move to lower energy levels
How have the models of the atoms changed?
1) . Tiny sphere
2) . Plum pudding model (sphere of positive charge with negative electrons embedded)
3) . Nuclear model (positive nucleus surrounded by negative electrons)
4) . Bohr model (electrons orbit nucleus at certain distances)
What were the conclusions found from the alpha scattering experiment?
- Most of the mass concentrated in nucleus
- Nucleus is positively charged
- Nucleus is mostly empty space
