## A portable x-ray unit has a step-up transformer. The 120 V input is transformed to the 100 kV output needed by the x-ray tube. The primary h

Question

A portable x-ray unit has a step-up transformer. The 120 V input is transformed to the 100 kV output needed by the x-ray tube. The primary has 47 loops and draws a current of 16 A when in use. What is the current output of the secondary in milliAmpere

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6 months 2021-08-25T08:08:48+00:00 1 Answers 0 views 0

1. The number of loops in the primary winding of the transformer draws our attention to it like some kind of consciousness-magnet.  But if and when we start to actually THINK about this question, we notice a subtle bad smell, and we realize that the number of loops in the transformer is a total red herring, and we don’t need to worry about it at all.

The electrical power coming out of the transformer is equal to the electrical power going into it.

Electrical power = (voltage) x (current)

— Power going in = (120 V) x (16 A) = 1,920 watts

— Power coming out = (100,000 V) x (current)

100,000v x current = 1,920 W

Current = 1,920 W / 100,000 V

Current = 0.0192 A

Current = 19.2 milliAmperes

Leave the red herring where we found it and let it rot.