Which of the transformers are step-up transformers? Which of the transformers are step-down transformers?

A transformer that has it secondary windings or output voltage more than its primary windings or voltage is a step up transformer

While A transformer that has it primary windings or output voltage more than its secondary windings or voltage is a step down transformer

In a step up transformer, the output voltage is greater than the input voltage while in a step down transformer, the output voltage is lesser than the input voltage

Explanation:

Transformer is a device that is used to convert one voltage level to another voltage level. It has two winding: the primary winding at the input and secondary winding at the output.

In a step up transformer, the output voltage is greater than the input voltage. Since the output and input current for a system is to be equal, the output current of a step up transformer is less than its input current. For a step up transformer, the number of turns in the secondary winding is greater than the number of turns in the primary winding.

In a step down transformer, the output voltage is lesser than the input voltage. Since the output and input current for a system is to be equal, the output current of a step down transformer is greater than its input current. For a step down transformer, the number of turns in the primary winding is greater than the number of turns in the secondary winding.

this could be newton#'s law of cooling. the cooling curve is exponential