Final answer:
In a step-up transformer with a 1 to 4 ratio, the current is correspondingly stepped down by a 1 to 4 ratio to maintain power balance, as voltage is increased by a factor of four.
Step-by-step explanation:
In a voltage step-up transformer with a ratio of 1 to 4, the current is stepped down by a 1 to 4 ratio. This is because the transformer operates under the principle that the power (the product of voltage and current) remains constant, assuming negligible resistance and high efficiency, which is common in practical transformers. When the transformer increases voltage, it compensates by decreasing the current to maintain the balance of power. Hence, if the voltage is increased by a factor of four, the current is reduced by a factor of four.