The energy conversion during the operation of an X-ray tube is:

Electrical→ thermal → mechanical (ke) → thermal and electromagnetic

(b)(i)Hardness = is the strength or penetrating power of the x-ray.
(iii)Intensity = is the energy radiated per unit time per unit area

(c)(i)Any four correct uses of the x-rays; e.g.

-Radio therapy
-Radiography
-Analytical tool in crystallography
-Cure of cancers
-Detection of fracture in bones
-In agriculture to kill germs
-At airports to detect metallic weapons
-In metals to detect defects and fractures.

(ii)Any ONE correct hazard of over exposure to x-rays: e.g.
-genetic mutations with undesirable hereditary consequences:
-leukemia
-skin burn/cancer
-tissue damage
-baldness,
-graying•
-cataracts.

The question on x-rays was fairly popular. However, the performance of the candidates was not impressive. Only very few candidates were able to draw acceptable diagrams of a modem x-ray tube. Most of the candidates could neither present correct diagram nor label their diagrams correctly. This led to a loss of 5 whole marks.

Though most of the candidates could recall all the energy transformations in the x-ray tube, most of them would not •arrange them in the correct sequence.

The candidates could not present acceptable descriptions of the mode of action of the x-ray tube due to poor language skills. The candidates' responses showed that the candidates were totally not familiar with the concept being tested. Almost all the candidates could not present any good definition for the hardness and intensity of x-rays; the uses of x-rays in everyday life and the hazards of x-rays were well handled by many candidates.