(a)(i) Properties of X-rays are:;
They (a) penetrates substance
(b) travel in straight lines
(c) are able to ionise gases.
(d) affect photographic plate or paper making them to fogge
(e) undergo reflection, or refraction, or polarization or diffraction etc.

(ii) X-rays are electromagnetic waves with wave properties such as;
- reflection
- refraction
- diffraction
- polarisation
- travel in straight line
- cannot be deflected by magnetic or electric field.

(iii) X - rays (a) used to ionise gases causing them to become conducting.
(b) used in industries to locate fractures in machines and metal castings.
(c) used to analyse crystal structure i.e. crystallography.

(iv) X - rays are hazardous because they
- kill mall organisms
- cause leukaemia can damage riving tissues
- cause genetic mutation
- cause damage to cells of large animals.
(b)(i) hf = eV
f = \(\frac{eV}{h}\)
f = 1% of eV = \(\frac{1 \times 1.60 \times 10^{-17} \times 5.00 \times 10^4}{100 \times 6.63 \times 10^{-34}}\) = 1.207 x 10\(^7\) Hz.
(ii) Times rate at which heat is removed = 99% x I x V
= \(\frac{99}{100}\) x 2.00 x 10\(^{-2}\) x 5.00 x 10\(^4\)
= 990W