(a) If only a fraction p of the electric power supplied is converted into x rays, at what rate is energy being delivered to the target?

(b) If the target has mass m and specific heat c (in J/kg ∙ K), at what average rate would its temperature rise if there were no thermal losses?

(c) Evaluate your results from parts (a) and (b) for an x-ray tube operating at 18.0 kV and 60.0 mA that converts 1.0% of the electric power into x rays. Assume that the 0.250-kg target is made of lead (c = 130 J/kg ∙ K).

(d) What must the physical properties of a practical target material be? What would be some suitable target elements?