P4 Radiation For Life

Question 1

How can electric shocks be avoided

Answer 1

If the object that is likely to become charged is connected to the earth through an earth wire
In a factory where machinery is at risk of becoming charged then the operator will stand on an insulating rubber mat

Question 2

What 2 things use static electricity to work

Answer 2

Dust precipitator, defibrillators and paint spraying

Question 3

How does a dust precipitator work

Answer 3

As the dust particles go up the chimney they are attracted to to the metal plate due to the metal plate having the opposite charge to the dust particles

Question 4

How does paint spraying work

Answer 4

The spray gun is charged, this gives all the paint particles the same charge, therefore these charges repel away from each other due to the fact that like charges repel, giving out a fine,even spray, the object is given the opposite charge to the paint so the paint is attracted to the obj ft and little paint is wasted

Question 5

How do defibrillators work

Answer 5

Two paddles are charged to a high voltage and placed frilly on the patients heart to ensure good electrical contact, then an el citric charge is passed through the the patient to make the heart contract

Question 6

What does the live wire, neutral wire and earth wire do

Answer 6

Live wire - carries voltage around the house
Neutral wire - completes the circuit providing a return path for the current
Earth wire - connected to the case of the appliance to prevent it becoming live, it stops a person receiving an electric shock as it makes the current flow back to the ground

Question 7

What are compressions in a wave and what are rarefactions

Answer 7

Regions of higher pressure and rarefactions are regions of lower pressure

Question 8

What are the features of longitudinal sound wave

Answer 8

Can’t travel through a vacuum, denser the medium the faster it travels, higher frequency smaller wavelength, louder the sound the higher the amplitude

Question 9

What is the difference between longitudinal waves and transverse waves

Answer 9

Longitudinal waves have vibrations of particles which go in parallel to the direction of the wave, transverse waves have vibrations of particles which go at right angles to the direction of the wave

Question 10

How is ultrasound used to break down kidney bones

Answer 10

High powered ultrasound is directed at the kidney stones and force them to vibrate extremely vigorously causing them to break into tiny pieces which can be excreted through urine

Question 11

How is ultrasound used in body scans

Answer 11

At each boundary between different tissues, some ultrasound is reflected back, the returning echoes come back at different times which builds up the image of the internal structure

Question 12

Why is ultrasound preferred to x-Rays

Answer 12

It is able to produce images of soft tissue and it doesn’t damage living cells

Question 13

What is the half life of a radioisotope

Answer 13

The average time for half the nuclei present to decay

Question 14

Why are alpha particles very good ionisers

Answer 14

Because they are the largest particles emitted in decay. This means that they a re more likely to strike atones of the material they are passing through, ionising them

Question 15

Where does most background radiations come form

Answer 15

Natural sources such as food, rocks like granite, cosmic rays from space and radioactivity naturally in the air

Question 16

How is gamma used to trace a blockage in a pipe and why

Answer 16

Game is used because it can penetrate the surface so it can be detected form the surface, and it is used by putting it into a pipe, a detector is passed along the ground above the path of the pipe, an increase in activity is detected at the leak and then there I little or no activity after this point

Question 17

How do smoke alarms work

Answer 17

The smoke detector releases alpha particles which ionise the air creating a tiny current that can be detected, smoke partially blocks this, so there is less ionisation of the air which the smoke detector picks up

Question 18

How can you date radioactive material such as uranium

Answer 18

The uranium isotopes in the rocks go through a series of decay and eventually forms a stable isotope of lead, by comparing the amount of lead and uranium present in a rock sample you can find an approximation of its age

Question 19

How does carbon dating work

Answer 19

All living the NGOs have carbon-14 present in it, when it dies carbon-14 stops being produced and decays, so the ratio of carbon-14 in the object shows how old it is

Question 20

How do x-rays work

Answer 20

High-speed electrons are fires at metal targets

Question 21

How can radioactivity be used as a tracer inside s patients body

Answer 21

Gamma radiation is put in the patients body through food , drink or injection, then it’s progress through the next Indy can be seen through a detector such as a gamma camera

Question 22

How are radioisotopes used to destroy a tumour in the body

Answer 22

Three sources of radiation are placed evenly around with the Timor being placed in the centre, and such of these give a third of the dosage, therefore healthy tissue only receives a third of the dose. The radiation should the destroy the tumour

Question 23

How does nuclear fission work in nuclear power stations

Answer 23

A neutron is absorbed by the nucleus of uranium-235 making it less stable so it splits and releases 3 neutrons, these neutrons then hit other uranium molecules and a chain reaction occurs

Question 24

How can nuclear fission be controlled

Answer 24

Firstly born control rods can be raised or lowered, then the boron absorbs the neutrons so fewer neutrons are available to split more uranium nuclei.
Also graphite moderators slow down the fast moving neutrons slowing down the process

Question 25

Revise fusion

Answer 25

Pg.38

Question 26

What happens to a polythene rod when it is rubbed with a duster

Answer 26

Electrons are transferred from the duster to the polythene rod, making the polythene rod negatively charged