The first ever x-ray of the human body was that of the hand of Wilhelm Roentgen's wife. Roentgen had accidentally discovered X-rays the week before, on November 8, 1895, and chose his wife's hand to demonstrate that X-rays could penetrate human soft tissue, but not our bones. The wavelength of the x-rays, produced by establishing a potential difference across a partially evacuated glass tube, was 0.124 nm, corresponding to a 10.0kV potential drop. Although modern x-ray machines have an average exposure time of 20 milliseconds and would deliver a dose equivalent of 60.0 nJ per gram of absorbing matter, Roentgen's first X-ray is estimated to have delivered 1,500 times this dose, with an exposure time of approximately 90 minutes.

(a) What was the frequency (in Hz) of the X-rays used by Roentgen to produce the first x-ray image?

Hz

(b) If the human hand has a mass of 250 g, what was the average power (in W) deposited into the hand of Roentgen's wife during the exposure?

 W

(c) Estimating the surface area of the hand in the x-ray image to be 129 cm², what was the magnitude of the electric field (in V/m) for the x-rays incident on the hand?