IDK Flashcards
describe the specific heat capacity practical (how to find the shc of a material)
First place will be corner balance and press zero next at the oil to the beaker and record the mass of the oil then place it thermometer and an immersion heater into the oil with the starting temperature of the oil and wrapped a beaker in insulating foam to reduce thermal energy transferred to the surroundings. Then connect a jewel meter and a power pack to the immersion heater that’s how many joules of electricity pass into the immersion heater. leave for 30 mins to allow temp to rise so we can accurately read on the thermometer next total the amount of energy to pass into the joule meter and read the final temperature of the oil you can then calculate the specific heat capacity by rearranging the formula.
What are some sources of inaccuracy with the shc practical
Thermal energy passing out of the beaker into the air- to combat this use an insulated with a lower thermal conductivity
Not all thermal energy passing into the oil to stop this ensure the immersion heater is fully submerged
An incorrect reading of the thermometer can be stopped by using an electronic temperature probe
To reduce the error of thermal energy not being spread through the oil you should stir the oil
How is electricity sent through the National grid?
Step up transformers increase potential difference from power stations in order to reduce the energy loss in the transmission cables step down transformer is reduce the potential difference before the electricity passes to homes
How are electrons moved form one insulator to another when rubbed together.- this. is static electricity btwwwww
When you rub an insulator onto another insulator insulator concerning electrons Moussa is electrons over to the other insulator for example of plastic rod moves its electrons to a cloth win this then makes the plastic rod positive and the cloth negative.
what does the variable resistor do
variable resistors do not have a fixed value – they can change their value as the current changes.
How to calculate the total current in a parralel circuit
add all of the different branches of current up
how do U calculate potential diff in series circuits/ parallel circuits
it is shared throughout the circuit/ it is kinda weird but basically its just the same per lane but is split into components in those lanes like a series circuit
What is Nuclear fission?
In some elements the nucleus is large and unstable for example uranium and plutonium . in nuclear fission the nucleus of these elements split- typically by the nucleus absorbing a neutron. When this happens this triggers the nucleus to undergo fission in other words to split. When the nucleus splits it forms to smaller daughter nuclei roughly equal in size along with two or three neutrons, some gamma radiation and energy. All of the fission products have kinetic energy. The neutrons can now be absorbed by more uranium nuclei and trigger fission again and so on. - Know as a chain reaction
What Are controlled and uncontrolled fission chain reaction is used for.
Controlled- for realising energy in a nuclear reactor
Uncontrolled- da big bomb tings
What is Nuclear Fusion?
A nuclear fusion to light nuclei such as hydrogen are joined to form a heavier nucleus.
Some of the mass of the nuclei can be with can be converted into energy which is released as radiation.
atomic history- if ur bored its dumb and nobody cares
In ancient Greece they believed that everything was made of atoms they also believed that atoms are tiny spheres that cannot be divided.
In 1897 scientists discovered that atoms contain tiny negative particles they called these electrons. This shows the atoms are not spheres that cannot be divided and that atoms have an internal structure.
I’m putting put the plum pudding model was that made it was believed to be a ball of positive charge containing just electrons.
they then did the Alpha scattering experiment which proved that the plum pudding model was incorrect.
We now call the central part of the atom the nucleus and created the nuclear model.
What is specific latent heat- SLH
Specific latent heat of the substance is the amount of energy required to change the state of 1 kg of the substance with no change in temperature.
What is the specific latent heat of fusion
The same as the specific latent heat except it’s just from 1 kg of a substance from a solid to a liquid.
It is the specific latent heat of vaporisation
It’s the same as the specific latent heat of fusion except is the energy required to change 1 kg of the substance from a liquid to a vapour
What is DC
THE CURRENT FROM A CELL IS A DIRECT CURRENT SITE FROM POSITIVE TO NEGATIVE as the electrons only move in One Direction
What is AC and what is its main benefit
Electricity in the UK is an alternating current. Main benefit is that it is very easy to use a transformer to increase or decrease the potential difference this is why we use it in the UK frequency of 50 Hz and a potential difference of around 230 V it takes about 0.1 seconds for it to change direction and 0.2 seconds per cycle
How to do alpha decay calculations
During alpha decay the top number typically the larger one gets increased by four and the bottom number, typically the smaller one is reduced by two this gives you the numbers for the other element
How to do Beta decay calculations
Add the small add one to the smaller number on the left and do nothing to the top number page decay is electron so it’s zero on the top and -1 the bottom
How to do gamma decay equations
Both the atomic number and mass number are not changed
What are the three core wires in the uk called and their colours/ what do they do
-The brown wire is the live wire and it carries the alternating potential difference from the supply (230 V) it is connected to the fuse
-The blue wire is called the neutral wire and it completes circuit. it has a potential difference 0 V compared TO THE LiveWire
-Green and yellow stripe wire is the Earth wire it is a safety wire to stop the appliance from becoming live.
Why is the live wire dangerous dangerous even if the circuit is broken via an open switch
The first part of the live wire still has a potential difference of 230 V
What does the earth wire do if the live wire touches a metal surface eg a washing machine
The case becomes live of a huge current flows to the Earth the fuse melts and shots of the current this is due to the wire being directly connected to the Earth
How do you test the effectiveness of thermal insulators?
First we place a small beaker inside a large beaker we then use a kettle to boil some water. Next we transfer 80 cm³ of the hot water into the small beaker and use a piece of cardboard with a small thermometer shaped hole in it as a lid for the large beaker. We then placed the ball with the monitor and the access monitor through the cardboard lid and the bulbs monitor must be in the hot water. Record the starting temperature of the water and begin to stopwatch we should then record the temperature of the water every three minutes for 15 minutes. Next we repeat the experiment with the same volume of hot water however this time is an insulating material such as bubblewrap to fill the gap between the two beakers. We should test with a range of materials e.g. cotton wool and POLYSTYRENE BALLS but use the same mass each time. Record the results for each material in a table and plot cooling curves for the different insulators.
How to we test how the thickness of a material affects thermal insulation?
Start with a beaker containing 80 cm³ of hot water Measure the temperature of the water every three minutes for 15 minutes repeat the experiment with two sheets of newspaper wrapped around it he then repeat the experiment two more times using four layers and then six layers of newspaper
What circuit do you need for the wire practical
A circuit set up with a battery a closed switch a volt meter in parallel to the wire an ammeter off the wire and that’s it
How to do wire practical
attach a wire to a meter ruler using tape. It’s a wire for the rest of the circuit using crocodile clips this means that only the part of the wider is between the two crocodile clips is actually connected to the circuit. Then use the different lengths of the wire to test the resistance which will help you find out the resistance and length of wire are directly proportional when put into a graph.
What could be some problems you come across when doing the wire practical.
Crocodile clips are hard to place at exactly 0 on a meter ruler there is also some resistance caused by the contact between the crocodile clip and the wire which both can cause zero errors.
If the temperature of the wire increases then the resistance will also increase- notice to combat this we should use a low potential difference which will keep the current low reducing any heating in the wire and only turn on the current when taking a reading so make sure to turn off the current between readings as well.
What is a zero error and how do you deal with it in the case of resistance
A zero error is a reading on a measuring instrument when the value should be zero
This is a systematic error we cannot reduce it by carrying out repeats
In the case of resistance we need to subtract the 0 from all our readings
What is a half life
The half-life of a radioactive isotope is the time it takes for the number of nuclei of the isotope in a sample to half.
Half life is also the time it takes for the count rate or activity from a sample containing the isotope to fall to half its initial level
Carry out the density practical using a vase
First measure the mass of the vase
Then filler eureka can until it starts overflowing and pouring out water
Once a year we can finish pouring out it’s water placed a vase inside and measure the volume displaced of water.
Then use the density formula to find the density using the mass and volume
What is the internal energy
Clinton energy is the energy stored in a system by the particles internal energy is the total kinetic energy and potential energy of all the particles (atoms and molecules) that make the system
What is correlation do the pressure of a gas and the volume of the gas have
The pressure of a gas is inversely proportional
Where does evaporation take place
It only takes place on the surface of the liquid is only the particles on the surface have enough energy to turn into a gas
The gas particles have a higher potential energy than liquid particles
Yes
