Physics Paper 1 Flashcards
What is specific heat capacity?
How hard it is to heat something up. The amount of energy needed to raise the temperature of 1kg of a substance by 1°C.
What is Power?
The rate of energy transfer, or rate of doing work.
What is the equation for power which includes work done?
Power (W)= Work done (j) / Time (s)
What is density?
How many of it’s particles have been squished into a given space.
How long is the radius of an atom?
About 0.1 nanometres
What are 4 features of a nucleus?
- Comtains protons and neutrons
- Positive charge
- Almost the whole mass of an atom is concentrated in the nucleus
What are 3 features of electrons?
- Move around the nucleus in shells
- Negatively charged
- No mass
Why do atoms have no charge?
Because it has the sam enumber of protons (+) and electrons (-)
What are ions?
Atoms that don’t have an equal amount of protons and electrons (so they will have a charge, e.g 2- charge will mean that it has two more electrons than protons).
What does the mass number of an element tell us?
Total number of protons + neutrons
What does the atomic number of an element tell us?
Total number of electrons (which is equal to the number of protons).
What is an isotope?
Atoms with the same atomic number as the element but a different mass number (which means it has the same number of protons/electrons but a different amount of neutrons).
What did John Dalton discover and in what year?
In 1804 he was the first person to describe atoms as solid spheres.
What did JJ Thomson discover and in what year?
In 1897 he created the plum pudding model, which explained that the atom is a ball of charge with electrons scattered.
What did Ernes Rutherford discover and in what year?
In 1909 he did the alpha scattering experiment.
What did Niels Bohr discover and in what year?
In 1911 he said that electrons re in shells orbiting the nucleus.
What did James Chadwick discover and in what year?
In 1940 he discovered that there are neutrons in the nucleus.
What were the 2 discoveries from the alpha scattering experiment?
Some Alpha particles were deflected back, which showed that most of the mass of an atom must be concnetrated at the centre in the tiny nucleus.
Most of the particles travelled straight through, which meant most of the stom is just empty space.
What happens when a atom emits an alpha particle?
Its atomic number reduces by 2 and it’s mass number reduces by 1.
What is an alpha particle?
An alpha particle is 2 eutrons and two protons (e.g lika a helium nucleus).
What is activity measured in?
Becauerals (Bq)
What is a half life?
The time taken for the number of radioactive nuclei in an isotope to halve.
What is Irradiation?
Exposure to radiation.
What is contamination in terms of radioactivity?
When radioactive particles get onto other objects.
