ConceptConceptDocsDocuments

CAIE A-Level Physics 24.2 Production and Use of X-Rays

Practise analysing X-ray production, minimum wavelength, attenuation, image contrast and CT reconstruction, including radiation exposure comparisons.

Syllabus
2028–2030
Course
Physics 9702
Level
A2

Exam points

  • explain X-ray production and calculate minimum wavelength from accelerating p.d.
  • interpret X-ray image contrast from material attenuation and transmitted intensity
  • calculate X-ray transmission or absorption using I = I?e??x
  • explain CT reconstruction from multiple angled images and sections
  • evaluate CT against single X-ray imaging, including 3D information and radiation exposure

Covered syllabus points

24.2.1—That X-rays are produced by electron bombardment of a metal target and24.2.2—The use of X-rays in imaging internal body structures24.2.3—I = I0e–µx for the attenuation of X-rays in matter24.2.4—Computed tomography (CT) scanning produces a 3D image of an internal

24.2 Production and use of X-rays question 1

[Maximum number: 6]

Question (a)

(a)

Fig. 8.1 shows a tube in which X-rays are produced at a metal target.

Fig. 8.1

Fig. 8.1

Particles are accelerated from the filament to the target by a constant high voltage applied across the terminals X and Y .

[ 2 ]

Question (i)

(i)

State the name of the particles.

[ 1 ]

Question (ii)

(ii)

On Fig. 8.1, use + and - signs to label terminals X and Y to indicate the polarity of the high voltage.

[ 1 ]

Question (b)

(b)

For an accelerating voltage of 32 kV in Fig. 8.1, determine:

[ 1 ]

Question (i)

(i)

the maximum energy, in MeV , of an X -ray photon produced at the target

maximum photon energy =MeV [1]
[ 1 ]

Question (c)

(c)

Explain why X-rays can be used to produce images of internal body structures that have good contrast.

[ 3 ]

24.2 Production and use of X-rays question 2

[Maximum number: 3]

Question (a)

(a)

State what is meant by contrast in an X-ray image.

[ 1 ]

Question (b)

(b)

A parallel beam of X-ray radiation is incident, separately, on samples of bone and of muscle.

Data for the thickness x of the samples of bone and of muscle, together with the linear attenuation coefficients μ\mu of the radiation in bone and in muscle, are given in Table 10.1.

Table 10.1

Table 10.1

Calculate the ratio
> intensity of radiation transmitted through the bone
> intensity of radiation transmitted through the muscle ⋅

ratio =

[ 2 ]
All question bank results loaded