Physics 2b Topics 4, 5 & 6

Question 1

List two factors which affect each of the two parts of the stopping distance

Answer 1

How fast your going and your reaction time

Question 2

Explain how seat belts, crumple zones and air bags are useful in a car crash.

Answer 2

They all reduce the force acting on you

Question 3

What are the units of power?

Answer 3

Watts (w)

Question 4

Explain what the mass number and atomic number of an atom represent.

Answer 4

The mass number is the number of protons and neutrons, The atomic number is the number of protons

Question 5

Explain what isotopes are. Do stable or unstable isotopes undergo nuclear decay?

Answer 5

Isotopes are atoms with the same number of protons in their nucleus, but a different number of neutrons. Unstable isotopes decay into other elements

Question 6

What are the properties of alpha radiation?

Answer 6

Alpha particles are positively charged. When an alpha passes close to an atom, it can pull a negatively charged electron away from the atom.

Question 7

What are the properties of beta radiation?

Answer 7

Beta particles are negatively charged. They can push electrons away from their atoms.

Question 8

What are the properties of gamma radiation?

Answer 8

Gamma rays can transfer energy to electrons. If the electron gets enough energy, it can break free from the atom

Question 9

Name a substance that will block each of the three types of radiation

Answer 9

Thick lead

Question 10

What is nuclear fusion?

Answer 10

Nuclear fusion is the joining of small nuclei

Question 11

What does a moderator do to neutrons in a nuclear reactor?

Answer 11

It slows down the fast moving neutrons

Question 12

Give three sources of background radiation

Answer 12

Decay of natural unstable isotopes, radiation from space and radiation due to human activity

Question 13

Give a definition of half-life

Answer 13

Half-life of a radioactive isotope is the time taken for half of the un-decayed nuclei to decay

Question 14

Which types of radioactive sources are used for the following:

a) smoke detectors
b) sterilisation of food
c) tracers in medicine
d) treating cancer

Answer 14

a) alpha radiation
b) gamma radiation
c) beta and gamma radiation
d) gamma rays

Question 15

Explain what kind of damage ionising radiation causes to body cells.

Answer 15

It can cause tissue damage and cell mutation

Question 16

List four safety precautions that should be taken when handing radioactive materials in the school lab.

Answer 16

Don’t be exposed to if for too long, never let it touch your skin, keep at arms length and keep it pointing away from the body

Question 17

What is the main problem with using nuclear power?

Answer 17

It creates radioactive waste which cannot be thrown away

Question 18

Give two advantages of using nuclear power to generate electricity

Answer 18

Its very reliable and reduces the need for fossil fuels

Question 19

What are two different parts of the overall stoping distance of a car?

Answer 19

Thinking distance and braking distance