physics year 10 mocks

What is the size of the radius of an atom

1 × 10^-10m

What is the size of the radius of a nucleus

1/10,000 of the atom

What is inside the nucleus

Protons and neutrons

How do electrons move from a lower energy level to a higher energy level

Electrons can move from a lower energy level to a higher energy level by the atom absorbing electrons magnetic radiation

How do electrons move from a higher energy level to a lower energy level

Electrons can move from a higher energy level to a lower energy level by emitting electromagnetic radiation

how do u determine the strength of an energy level

The energy level with the most strength is the one furthest away from the nucleus

What is the number at the top of an element

The number at the top of an element is the mass number containing protons and neutrons

What is the number at the bottom of an element

The number at the bottom of an element is the atomic number which shows the number of protons and is equal to the number of electrons

How do u work out the number of neutrons inside the nucleus

To work out the number of neutrons inside the nucleus you can do mass number - atomic number

Explain history of beliefs of atoms

Ancient Greeks thought atoms were indivisible tiny spheres

1897 proved that there was something inside the atoms that gave it negative charge disproving this

Plum pudding model was made to show that the atom is a ball of positive charge with negative charge embedded within it

Nucleur model disproves this ppm as the atom is mainly made of empty space the positive charge and mass is concentrated in the nucleus

Bohr then discovered electrons orbit the nucleus at distances (energy levels)

Explain the alpha particle experiment

Gold foil was used as it can be hammered into a thin sheet of foil just a few atoms thick

Alpha particle shooter was used, alpha particles have positive charge

Observations

Most the particles went straight through the gold foil meaning most the atom was empty space, disproving the plum pudding model as it stated the atom is a ball of positive charge with negative electrons embedded within indicating that the atom wasn’t mainly empty space

Some of the alpha particles were deflected showing that the centre of the atom must have a positive charge which repelled the particles this disproves the ppm as the ppm states it is a ball of positive charge with negative electrons embedded with meaning that it wasn’t just the centre of the atom that had a positive charge

Some of the alpha particles bounced straight back indicating the centre of the atom was mass concentrated disproving the ppm as it starred atom is ball of positive charge with negative electrons embedded within meaning the mass was spread across the whole atom

What is an isotope

An isotope is an atom of the same element with a Different number of neutrons

Some isotopes may be un___ and may d____ producing r_____ other wise known as r___ d___

Some isotopes may be unstable and decay producing radiation and this process otherwise known as radioactive decay

What are the three types of radiation given out in radioactive decay

He three types of radiation are

Alpha

Beta

Gamma

List the penetration for each radiation

Gamma is stopped by several centimetres of thick lead (high)

Beta is stopped by 3mm thick sheet of aluminium (mid)

Alpha is stopped by a few cm of paper or air (low)

List the ionising power of each radiation

Alpha is very ionising

Beta is quite ionising

Gamma has weak ionising

List what each radiation actually is

Alpha particles are helium nucleuses ( contain 2 protons and 2 neutrons)

beta particles are high speed electrons

Gamma rays are high frequency electromagnetic radiation

List the charges of the radiations

Alpha +2

Beta -1

Gamma 0

Write notations for each radiation and hence what happens in equation

Alpha particle /He has mass number of 4 an atomic number of 2

In an equation the mass number falls by 4 and atomic number falls by 2 of the nucleus decaying

Beta particle / electron has 0 mass number and -1 atomic number

In an equation the nucleus that is decaying has unchanged mass number and the atomic number increases by 1

Gamma has 0 everything

In an equation nothing happens (unchanged)

How is radiation detected

Radiation is detected using a Geiger muller tube

How does a Geiger Muller tube work

A Geiger Muller tube registered a click every time it receives a decay particle or ray

What does the number of clicks on a Geiger muller tube show

The number of decay per second (activity)

What is activity measured in

Activity is measured in Becquerels (Bq)

explain half life

Half life is the time it takes for the nuclei of an unstable isotope to halve

Any single decay is random and unpredictable

What does irradiation meaning

Irradiation means being exposed to radiation

If something is irradiated it means it does not become radioactive

How do you protect against radioactive sources

shield with lead

What is contamination

Radioactive material being present where it shouldn’t be

Explain the harm of radiation

Alpha particles inside the body are extremely dangerous as they are highly ionising and can damage vital organs but outside the body it is not that harm ugly as it can’t penetrate that well to ge inside

Beta and gamma particles are highly dangerous outside the body as they can penetrate easily to get inside the body as they are more penetrating power than alpha and they can reach organs

What Is radiation dose measured in and what is it

Radiation dose is measured in Sieverts (Sv). It is a measure of harm due to radiation

what are the uses of radiation

Alpha radiation is used in smoke detectors because it is highly ionising allowing current to flow in the detector as it ionises the air. Smoke blocks the radiation causing current to fall triggering the alarm

Beta emissions is used to check the thickness of sheets of paper or metal, the amount of radiation is measured that passes through sheet of too high it’s thin if too low it’s thick

Gamma radiation is very penetrating so it is used for crack detection in metal pipes and for sterilising medical equipment. It can also kill cancer cells

What is nuclear fission and fusion

Nuclear fission is the splitting of an unstable atomic nucleus into two

Nuclear fusion is the joining of two atomic nuclei to form a heavier nucleus

They both release huge amounts of energy

How does fission process work

A nucleus will absorb a neutron and split into two nucleuses and 2-3 neutrons releasing a lot of energy in the form of gamma rays . The other neutrons will go onto cause fission in other nucleuses

What happens to the particles released

The two nucleus will collide with atoms around it rapidly losing kinetic energy and converting it into heat and because they are unstable they will undergo radioactive decay. The neutrons will cause fission for other nuclei an gamma rays release energy

What is background radiation

Background radiation is low levels of radiation that is around us at all times