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Subjects · Leaving Cert Physics & Chemistry

Leaving Cert Physics & Chemistry: Nuclear energy

How often Nuclear energy comes up on the Physics & Chemistry papers, every year it was asked, and questions to try.

HL Asked on 9 of the last 9 Higher Level papers, most recently in 2025. banker

OL Asked on 8 of the last 9 Ordinary Level papers, most recently in 2025. most years

Nuclear energy, Higher Level(7 marks)

Quick ones on Nuclear energy.

(a)What is nuclear fission?
  1. Joining of two light nuclei to form a heavier one
  2. Splitting of a heavy nucleus into two smaller nuclei
  3. Emission of an alpha particle from a nucleus
(b)What is the source of the Sun's energy?
  1. Burning of hydrogen gas in oxygen
  2. Fission of uranium nuclei
  3. Fusion of hydrogen nuclei into helium
(c)In a nuclear reaction 2.0 × 10⁻²⁸ kg of mass is lost. Energy released? (c = 3.0 × 10⁸ m s⁻¹)
  1. 1.8 × 10⁻¹¹ J
  2. 2.2 × 10⁻⁴⁵ J
  3. 6.0 × 10⁻²⁰ J
Show the answers

(a) Splitting of a heavy nucleus into two smaller nuclei

(b) Fusion of hydrogen nuclei into helium

(c) 1.8 × 10⁻¹¹ J

Your turn: Higher Level questions on Nuclear energy.

Higher Level

Asked on 9 of the last 9 Higher Level papers, most recently in 2025. banker

Every paper, year by year

YearWhere it came up
2025Q1(p), Q1(r)
2024Q1(q), Q1(r)
2023Q6(d)
2022Q1(q), Q1(r)
2021Q6(d)
2019Q6(d)
2018Q1(n)
2017Q1(n), Q1(o)
2016Q1(o)

Links open the State Examinations Commission’s paper for that year.

More Nuclear energy questions

Nuclear energy, 3 marks

Why is nuclear fusion not yet used to generate electricity?

  1. It produces very large amounts of long-lived radioactive waste
  2. Its hydrogen fuel is extremely rare and has to be mined
  3. The very high temperatures needed are very hard to contain
Show the answer

The very high temperatures needed are very hard to contain

Fusion needs temperatures of millions of degrees so nuclei can overcome their repulsion. Holding such hot material is not yet practical. Its fuel (hydrogen isotopes) is plentiful.

Ordinary Level

Asked on 8 of the last 9 Ordinary Level papers, most recently in 2025. most years

Every paper, year by year

YearWhere it came up
2025Q1(q), Q1(r)
2024Q1(r)
2023Q1(r)
2022Q1(r)
2021Q1(r)
2019Q1(o)
2018Q1(o)
2017Not asked
2016Q1(n)

Links open the State Examinations Commission’s paper for that year.

More Nuclear energy questions

Nuclear energy, 2 marks

Nuclear fission is?

  1. Joining of two small nuclei into a larger one
  2. Emission of an electron from an unstable nucleus
  3. Splitting of a large nucleus into two smaller ones
Show the answer

Splitting of a large nucleus into two smaller ones

A slow neutron hits a uranium-235 nucleus, which splits, releasing energy and more neutrons. Joining small nuclei is fusion.

Nuclear energy, 2 marks

Nuclear fusion is the source of the energy of?

  1. A coal-fired power station
  2. The Sun
  3. A nuclear power station
Show the answer

The Sun

In the Sun, hydrogen nuclei join to make helium, releasing huge energy. Nuclear power stations use fission; coal stations burn fuel.

Nuclear energy, 2 marks

In a nuclear reactor, what keeps the chain reaction going?

  1. Neutrons released by each fission
  2. Electrons released by each fission
  3. Alpha particles from the fuel
Show the answer

Neutrons released by each fission

Each fission releases 2 or 3 neutrons, which can split more nuclei. Control rods absorb some neutrons so the reaction stays steady.

Other Physics & Chemistry topics

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