Suggest a way to establish, without using an ammeter, if there is current in the wire. How to determine the direction of the current?

To determine if there is a current in the conductor, you need to bring a magnetic needle to it. If the arrow deviates, it means that there is current in the conductor. since there is a magnetic field around the current conductor. You can find the direction of the current in the conductor by the steady position of the arrow.

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