LONGER ANSWERS PAPER 1

Question 1

Explain the changes in the arrangement and movement of the particles as the ice
melted and the temperature increased to 5 °C. (6)

Answer 1

• particles in a solid are in a regular pattern
• particles in a liquid are in a random arrangement
• particles in a solid are vibrating about fixed positions
• particles in a liquid are moving freely
• as the ice changes to water the temperature remains constant
• because as the ice changes to water the potential energy of the
  particles increases
• as the water warms the particles move faster
• so the kinetic energy of the particles increases
• internal energy is the total kinetic and potential energy of all the
  particles

Question 2

what effect does half life of an isotope have on a person’s health?

Answer 2

the shorter the half life, the more radiation emitted per second, greater activity, greater dose of radiation absorbed per second

Question 3

A worker stands 1 cm away from a radiation detector.
The amount of radiation the worker emits is recorded.
Explain why the worker needs to stand close to the radiation detector.

Answer 3

some radioactive materials emit
alpha radiation which has a short range in air

Question 4

Explain how an electron can move up and down between energy levels in an atom (2)

Answer 4

• to move to a higher energy level
  an electron absorbs energy
  from electromagnetic radiation
• to move to a lower energy level
  an electron emits energy in the
  form of electromagnetic
  radiation

Question 5

The air pressure in a car tyre changes if the temperature of the air in the
tyre increases.
Explain why.

Answer 5

• as temperature increases the
  air particles have greater kinetic energy
• so more collisions with tyre
  walls per second
• greater force in each
  collision
• greater force per square
  metre causes greater pressure on wall

Question 6

describe the experiment that led to the development of nuclear model (6)

Answer 6

• alpha particle scattering experiment
• alpha particles directed at gold foil
• most alpha particles pass straight through so most of the particles pass straight through
• a few particles DEFLECTED at large angles so mass is centred at the centre of the atom and nucleus is positively charged
  -ppm had mass spread throughout the atom
  -ppm has charge spread throughout the atom

Question 7

explain how the distance at which an elector orbits the nucleus might be changed

Answer 7

• electron may absorb electromagnetic radiation
• move further from the nucleus
• to a higher energy level

Question 8

explain what happens in the process of nuclear fusion

Answer 8

• two light nuclei join to form a heavier nucleus
• the mass of nuclei is converting to energy
• some of the mass is converted into the energy of radiation

Question 9

describe the process of nuclear fusion

Answer 9

nucleus absorbs a neutron and splits into two smaller nuclei and releases 2 neutrons and energy

Question 10

what are the advantages of fusion reaction of fission reaction

Answer 10

• produces little/no radioactive waste