Physics · Magnetism and Electromagnetic Induction

In a step-up transformer, the relationship between primary and secondary voltage and current is governed by the equation: V_p / V_s = I_s / I_p, where V represents voltage and I represents current for primary (p) and secondary (s) coils. When the secondary voltage is increased by a factor of 10, the equation indicates that the secondary current must decrease correspondingly to maintain energy conservation. Thus, if the voltage increases by a factor of 10, the current in the secondary coil must decrease to one-tenth of the primary current, which is represented by Option D.

The other options are incorrect because they misinterpret the inverse relationship between voltage and current in a transformer. For example, saying the secondary current is 10 times higher or equal to the primary current ignores the fundamental principle that as voltage increases, current must decrease.

This option suggests that when the voltage increases, the current also increases, which contradicts the principle of conservation of energy in transformers.

This option indicates a decrease in current, which aligns with the expected behavior of a step-up transformer. However, the correct relationship should specify that the current is one-tenth of the primary current, not just lower by a factor of 10.

This option implies that current remains constant, which is incorrect for a step-up transformer where voltage increases and current decreases.

This option correctly reflects the principle of a step-up transformer, where an increase in secondary voltage leads to a proportional decrease in secondary current.