S3 EXAM Flashcards
Electrical current
Electric charge transferred per unit time
What do charged particles experience ?
Charged particles experience a force in an electric field
potential difference
a measure of the energy given to a charge carrier in a curcuit
TURD
the temperature of a conductor increases, the resistance of the conductor increases
ametere
measure amps in a curcuit
votlmeter
measure potential difference in a curcuit
ohmeter
measures the resistance in a curcuit
transister
an electric switch in a curcuit
electrical power
the amount of energy trasfered per unit time
effect of an increases in potetial diffrence
an increase in potetial diffrerence across a componant will increase the power developed across that componant
appropriate fuses
a 3A fuse should be selected for most appliences rated up to 720W, a 13A fuse for appliences rated over 720W
ionistation
the addition or removal of an electron from an atom
effect of ionisation on an atom
this will turn a neutrally charged atom positively or negetively charged ion
types of radiation
alpha, beta, gamma
what happens when radiation is emitted from the nucleus
energy is released, the energy is usally absorbrd by the medium through which the radiation is passing through
x-rays can cause ionisation. explain what is meant by ionisation
when an atom gains or loses electrons
alpha
helium nucleus
positively charged
slow and heavy
extremely ionising
beta
electrons
negetively charged
fast moving
gamma
high frequency waves
travel speed of light
no mass no electrical charge
weakly ionising
state two factors which can affect the background radiation level
the radon gas found in rocks and radiation that reaches earth from outer space a s cosmic rays
radiation safety procedures
limit time exposed to radiation
wear protective clothing
wash hands after using a radioactive source
don’t touch a radioactive source
applications of radiation
radiotherapy - gamma rays kill cancer cells and identify tumour
radioactive tracers- gamma rays to help diagnose illnesses
smoke detecter- alpha radiation easily absorbed by smoke detecter
activity
the number of nuclei decaying per second
absorbed dose
the energy absorbed per unit mass of the absorbing material
equivelent dose
the measure harm that could happen by radiation
weigting factor
the measure of the biological effects of radiation
half life
time for activity to drop yo half its value
nucleur fission
nucleur fission happens when the nucleus of an atom is split in two, which causes a large amount of energy. this continues to happen causing a chain reaction
nucleur fusion
nucleur fusion is the process which the nuclei of light elements combine or fuse togther, releasing a large amount of energy
advantage and disandvantage of fusion
releases a large amount of energy more than nucleur fission
it is hard to acheive and needs large amounts of energy
scaler quantities
is magnetude e.g energy distance speed
vector quantities
magnitude and direction e.g acceleration, velocity, force
velocity
speed of something in a given direction
distance
the total length of path travelled
displacement
the length and direction of a straight line from start to finish
speed
the distance travelled each second
instantaneous speed
the speed of an object at any given time
length of card divided by the time to pass through the light gate
acceleration
the change in velocity per unit time
state the acceleration of 2ms-2
the acceleration of 2ms-2 means that every second, the velocity increases by 2ms-1
effect of forces
change the shape of an object
change the speed of an object
change the direction of a moving object
friction
fiction acts between ant 2 surfaces in contact, it acts in the opposite direction to movement
how can friction be reduced
reducing surface contact
creating an air gap
friction effect on energy
friction causes energy to be transformed the heat energy which is usally lost to surroundings
air resistance
a resistive force that can be reduced by steamlining an object
balanced forces
when forces are equal in size but opposite in direction they are said to be balanced. this means there in no force and remains at rest or travelling at a consatant speed in a straight line
examples of everyday unbalanced forces
friction, air resistance, weight
newtons first law
an object will remain at rest or travel at the same speed, in a straight line unless an unbalanced force acts on the object
newtons second law
an object will accelerate in the same direction of the unbalanced force acting on it. the magnitude of the acceleration is also porportional to the magnetude of the unbalanced force
mass
mass is a measure of the amount of matter in an object. the mass value does not change from place to place
weight
a force caused by a gravitational force acting on an objects mass
gravitational field strength
is the weight per unit mass
newtons third law
if object A exerts a force on object B, then object B will exert an equal, but opposite force on object A
if an object is at rest or accelerating in a straight line then it is called …
terminal velocity or constant speed
radiation weighting factor: gamma beta alpha fast neutrons thermal neutrons x-ray
1 1 20 10 3 1
average annual background radiation
2.2 mSv
annual effective dose limit for public
1mSv
annual effective dose limit for radiation worker
20mSv
