1. Birds resting on high-voltage power lines are a common sight. The copper wire on which a bird stands is 2.2cm in diameter and carries a current of 50A. If the bird's feet are 4.0cm apart, calculate the potential difference across its body.
2. An x-ray tube used for cancer therapy operates at 4.0MV, with a beam current of 25mA striking the metal target. Nearly all the power in this beam is transferred to a stream of water flowing through holes drilled in the target. What rate of flow, in kilograms per second, is needed if the temperature rise (delta t) of the water is not to exceed 50degreesC?