Wantirna College Yr 11 Physics Unit 1 Nuclear Physics

Chapter test. 2011

Part A

Questions 1 to 4 refer to the following information.
There are two main isotopes of uranium: and . Only the isotope undergoes fission.
Question 1
Why are and said to be isotopes?
(1 mark)
Question 2
In the space below, state the number of protons and neutrons in an atom of .

(2 marks)
Question 3
The nuclei of these isotopes contain many positively charged protons. Explain why the nuclei do not disintegrate under the force of electrostatic repulsion.
(2 marks)
Question 4
What is nuclear fission?
(1 mark)
Questions 5 & 6 refer to the following information.
When an atom of undergoes fission, it generally forms two fission fragments and releases a number of neutrons.
Question 5
Here is a fission reaction that has two unknown quantities in it:

What are the values of unknowns a and b in the above fission reaction?

(2 marks)
Question 6
What type of neutron is released by the fission of atoms?
(1 mark)
Questions 7 & 8 refer to the following information.
The diagram below shows the core of a nuclear reactor.

Question 7
(a)  What is the function of the control rods?
(1 mark)
(b)  How is this function achieved?
(1 mark)
Question 8
State two functions of the coolant in a nuclear reactor.
(2 marks)
Questions 9 & 10 refer to the following information.
Plutonium 239Pu is an artificial element. It is formed in nuclear power plants when atoms of absorb neutron in fuel rods. 239Pu can also undergo fission.
Question 9
Describe in words, or write an equation to show, how this event forms an atom of 239Pu.
(3 marks)
Question 10
Nuclear fusion occurs naturally in the Sun. What is nuclear fusion? Give an example.
(2 marks)

Part B

Questions 1 to 5 refer to the following information.
There are three naturally occurring types of nuclear radiation, alpha (a), beta (b) and gamma (g).
Question 1
What is b– radiation identical to?
(1 mark)
Question 2
Describe how radiation occurs.
(2 marks)
Question 3
What happens to the atomic number and mass number of an atom when it undergoes decay?
(2 marks)
Question 4
Arrange the types of naturally occurring radiation in order from most penetrating to least penetrating.
(1 mark)
Question 5
Arrange the types of naturally occurring radiation in order from most ionising to least ionising.
(1 mark)
Questions 6 to 9 refer to the following information.
is an isotope of the element radon. It has a half-life of 23 minutes and decays by emitting an alpha particle.
Question 6
What is an a particle identical to?
(1 mark)
Question 7
State the number of protons and neutrons in the nucleus of an atom of .

(2 marks)
Question 8
What are the atomic and mass numbers of the daughter nucleus formed when undergoes a decay?

(2 marks)
Question 9
At a particular moment, a sample of radon gas contains 128 g of .
(a)  What mass of remains 23 minutes later?
(1 mark)
(b)  What mass of remains 46 minutes later?
(2 marks)
Question 10
Write a nuclear equation to show the a decay of to form an isotope of thorium (Th).
(3 marks)
Questions 11 & 12 refer to the following information.
The terms ‘absorbed dose’ and ‘dose equivalent’ are used to determine the effects of radiation exposure on living organisms.
Question 11
What does the ‘absorbed dose’ describe?
(1 mark)
Question 12
What is meant by the term ‘dose equivalent’ and how is it related to the absorbed dose?
(2 marks)
Questions 13 to 15 refer to the following information.
The table below gives the approximate quality factors of different types of radiation.

A 65 kg person absorbs 0.045 J of energy due to ionising radiation.
Question 13
Calculate the absorbed dose in this case.
(2 marks)
Question 14
What is the dose equivalent if the energy is delivered by γ rays?
(2 marks)
Question 15
What is the dose equivalent if the energy is delivered by a particles with a quality factor of 12?
(2 marks)