Subjects · Leaving Cert Physics
Leaving Cert Physics: X-rays
How often X-rays comes up on the Physics papers, every year it was asked, and questions to try.
HL Asked on 7 of the last 10 Higher Level papers, most recently in 2024. most years
OL Asked on 8 of the last 10 Ordinary Level papers, most recently in 2025. most years
June 2027 is the first exam on the new Physics course. These come from the 2016–2026 papers, so read them as a guide.
Quick ones on X-rays.
- The sound spectrum
- The electromagnetic spectrum
- The alpha particle spectrum
- Measuring the speed of cars on a motorway
- Cooking food quickly in a commercial oven
- Detecting cracks and flaws inside metal castings
- 8.0 × 10⁻¹⁵ J
- 3.2 × 10⁻²⁴ J
- 8.0 × 10⁻¹⁴ J
Show the answers
(a) The electromagnetic spectrum
(b) Detecting cracks and flaws inside metal castings
(c) 8.0 × 10⁻¹⁵ J
Higher Level
Asked on 7 of the last 10 Higher Level papers, most recently in 2024. most years
Every paper, year by year
| Year | Where it came up |
|---|---|
| 2026 | Not asked |
| 2025 | Not asked |
| 2024 | Q10 |
| 2023 | Q10 |
| 2022 | Q6(k) |
| 2021 | Q12 |
| 2019 | Q8 |
| 2018 | Q5(f) |
| 2017 | Q10 |
| 2016 | Not asked |
Links open the State Examinations Commission’s paper for that year.
More X-rays questions
X-rays, 3 marks
How are X-rays produced in an X-ray tube?
- A metal target is heated until it glows and gives out rays
- Heavy nuclei in the metal target split into two lighter nuclei
- Fast-moving electrons are suddenly stopped by a metal target
Show the answer
Fast-moving electrons are suddenly stopped by a metal target
Electrons accelerated through a high voltage strike a tungsten target and their kinetic energy becomes X-ray photons. Over 99 per cent becomes heat.
X-rays, 2 marks
How is X-ray production related to the photoelectric effect?
- It is the same: both need the metal to be heated before they work
- It is the reverse: electron kinetic energy is turned into photon energy
- It is the same: both release electrons when light shines on a metal
Show the answer
It is the reverse: electron kinetic energy is turned into photon energy
Photoelectric: a photon goes in, an electron comes out. X-ray tube: a fast electron goes in, a photon comes out. Energy is conserved in both.
X-rays, 2 marks
Which part of an X-ray tube gives out the electrons?
- A heated filament (the cathode)
- The metal target (the anode)
- The glass wall of the tube
Show the answer
A heated filament (the cathode)
The hot filament releases electrons by thermionic emission. A high voltage accelerates them to the target, where they are stopped and X-rays are produced.
Ordinary Level
Asked on 8 of the last 10 Ordinary Level papers, most recently in 2025. most years
Every paper, year by year
| Year | Where it came up |
|---|---|
| 2026 | Not asked |
| 2025 | Q14(d) |
| 2024 | Q13 |
| 2023 | Q12 |
| 2022 | Q12 |
| 2021 | Q6(i) |
| 2019 | Q10 |
| 2018 | Q10 |
| 2017 | Not asked |
| 2016 | Q10 |
Links open the State Examinations Commission’s paper for that year.
More X-rays questions
X-rays, 2 marks
Give one medical use of X-rays.
- Measuring the speed of blood flow
- Measuring body temperature
- Finding broken bones
Show the answer
Finding broken bones
X-rays pass through soft tissue but are absorbed by bone. Blood-flow speed is measured with Doppler ultrasound.
X-rays, 2 marks
Why does a radiographer stand behind a lead screen when taking X-rays?
- Lead makes the X-rays stronger
- X-rays are harmful and lead absorbs them
- Lead reflects the X-rays back at the patient
Show the answer
X-rays are harmful and lead absorbs them
X-rays are ionising and can damage cells. The radiographer takes X-rays many times a day, so must be shielded.
X-rays, 2 marks
Why does bone show up clearly on an X-ray photograph?
- Bone absorbs X-rays much more than soft tissue does
- Bone gives out its own X-rays
- Bone reflects visible light onto the film
Show the answer
Bone absorbs X-rays much more than soft tissue does
Fewer X-rays get through bone to reach the film or detector, so bones show up white and the soft tissue dark.
Other Physics topics
- Diffraction
- Gravity
- Interference
- Magnetic fields
- Mandatory experiments
- Nuclear energy
- Radioactivity
- Refraction
- Resonance
- Sound
- Static electricity
- The photoelectric effect
- Wave properties
- Circuits
- Circular motion
- Density and pressure
- Latent heat
- Linear motion
- Resistance
- Simple harmonic motion
- Work energy and power
- Capacitance
- Doppler effect
- Heat transfer
- Moments
- Momentum
- Reflection
- Semiconductors
- The motor effect
- Colour of light
- Domestic electricity
- Electromagnetic induction
- Heat capacity
- Newton's laws
- Temperature
- The atom
- The electron
- Current electricity
- Forces
- Lenses
- Thermometers
- Alternating current
- The electromagnetic spectrum
- Transformers