Keiko builds a transformer in the lab, but it does not decrease the voltage as much as she needs. what should keiko change to further reduce the voltage? she should make the number of coils in the primary winding less than in the secondary winding. she should make the number of coils in the primary winding the same as in the secondary winding. she should increase the number of coils in the secondary winding. she should increase the number of coils in the primary winding.

She should increase the number of coils in the primary winding.

Explanation:

Transformers work on the principle of Faraday's electromagnetic induction between both the coils of a transformer mutually together. This process is also called mutual induction.

According to the Faraday's law of electromagnetic induction states that when a flux linked to a circuit changes, an emf is induced in the circuit proportional to the rate of change in flux.

This induced emf between the two windings is determined by the number of turns in primary and secondary winding respectively.

For a transformer:

where:

are the no. of turns in the primary and secondary coils of the transformer respectively.

are the voltages in the primary and secondary coils of the transformer respectively.