What is the current in the secondary coil fi the current in the primary coil is 5.0A 10 loops on primary coil and 20 on secondary coil?

If I am not wrong then you have asked about a transformer. And its a current transformer. By theory of voltage transformer we know that

Vs/Vp = Ns/Np

So for answering your question we need the value of number of turns in primary and secondary coil. But you can use this equation to find your answer if you have other values. By using ohmic law you can convert voltage to current.